Modulators of sestrin-gator2 interaction and uses thereof

ABSTRACT

The present invention provides compounds, compositions thereof, and methods of using the same.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to compounds and methods useful for modulating the Sestrin-GATOR2 interaction thereby selectively modulating mTORC1 activity indirectly. The invention also provides pharmaceutically acceptable compositions comprising compounds of the present invention and methods of using said compositions in the treatment of various disorders.

BACKGROUND OF THE INVENTION

The mechanistic target of rapamycin complex 1 (mTORC1) protein kinase is a master growth regulator that senses diverse environmental cues, such as growth factors, cellular stresses, and nutrient and energy levels. When activated, mTORC1 phosphorylates substrates that potentiate anabolic processes, such as mRNA translation and lipid synthesis, and limits catabolic ones, such as autophagy. mTORC1 dysregulation occurs in a broad spectrum of diseases, including diabetes, epilepsy, neurodegeneration, immune response, suppressed skeletal muscle growth, and cancer among others (Howell et al., (2013) Biochemical Society transactions 41, 906-912; Kim et al., (2013) Molecules and cells 35, 463-473; Laplante and Sabatini, (2012) Cell 149, 274-293).

Many upstream inputs, including growth factors and energy levels, signal to mTORC1 through the TSC complex, which regulates Rheb, a small GTPase that is an essential activator of mTORC1 (Brugarolas et al., (2004) Genes &amp; Development 18, 2893-2904; Garami et al., (2003) Molecular Cell 11, 1457-1466; Inoki et al., (2003) Genes &amp; Development 17, 1829-1834; Long et al., (2005) Current Biology 15, 702-713; Sancak et al., (2008) Science (New York, N.Y.) 320, 1496-1501; Saucedo et al., (2003) Nature cell biology 5, 566-571; Stocker et al., (2003) Nature cell biology 5, 559-565; Tee et al., (2002) Proc Natl Acad Sci USA 99, 13571-13576). Amino acids do not appear to signal to mTORC1 through the TSC-Rheb axis and instead act through the heterodimeric Rag GTPases, which consist of RagA or RagB bound to RagC or RagD, respectively (Hirose et al., (1998) Journal of cell science 111 (Pt 1), 11-21; Kim et al., (2008) Nature cell biology 10, 935-945; Nobukuni et al., (2005) Proc Natl Acad Sci USA 102, 14238-14243; Roccio et al., (2005) Oncogene 25, 657-664; Sancak et al., (2008) Science (New York, N.Y.) 320, 1496-1501; Schurmann et al., (1995) The Journal of biological chemistry 270, 28982-28988; Sekiguchi et al., (2001) The Journal of biological chemistry 276, 7246-7257; Smith et al., (2005) The Journal of biological chemistry 280, 18717-18727). The Rag GTPases control the subcellular localization of mTORC1 and amino acids promote its recruitment to the lysosomal surface, where the Rheb GTPase also resides (Buerger et al., (2006) Biochemical and Biophysical Research Communications 344, 869-880; Dibble et al., (2012) Molecular cell 47, 535-546; Saito et al., (2005) Journal of Biochemistry 137, 423-430; Sancak et al., (2008) Science (New York, N.Y.) 320, 1496-1501). Several positive components of the pathway upstream of the Rag GTPases have been identified. The Ragulator complex localizes the Rag GTPases to the lysosomal surface and, along with the vacuolar-ATPase, promotes the exchange of GDP for GTP on RagA/B (Bar-Peled et al., (2012) Cell 150, 1196-1208; Sancak et al., (2010) Cell 141, 290-303; Zoncu et al., (2011) Science Signaling 334, 678-683). The distinct FLCN-FNIP complex acts on RagC/D and stimulates its hydrolysis of GTP into GDP (Tsun et al., 2013). When RagA/B is loaded with GTP and RagC/D with GDP, the heterodimers bind and recruit mTORC1 to the lysosomal surface, where it can come in contact with its activator Rheb GTPase.

Recent work has identified the GATOR1 multi-protein complex as a major negative regulator of the amino acid sensing pathway and its loss causes mTORC1 signaling to be completely insensitive to amino acid starvation (Bar-Peled et al., (2013) Science 340, 1100-1106; Panchaud et al., (2013) Science Signaling 6, ra42). GATOR1 consists of DEPDC5, Npr12, and Npr13, and is a GTPase activating protein (GAP) for RagA/B. The GATOR2 multi-protein complex, which has five known subunits (WDR24, WDR59, Mios, Sec13, and Seh1L), is a positive component of the pathway and upstream of or parallel to GATOR1, but its molecular function was, until recently, unknown (Bar-Peled et al., (2013) Science 340, 1100-1106).

Recently, additional information about the mTORC1 pathway has been elucidated by identifying the binding of GATOR2 with one or more of the Sestrins and demonstrating that the resulting Sestrin-GATOR2 complex regulates the subcellular localization and activity of mTORC1. In particular, the presence of Sestrin-GATOR2 complexes inhibits the mTORC1 pathway and decreases mTORC1 activity by preventing translocation of mTORC1 to the lysosomal membrane. Interaction of GATOR2 with the Sestrins, and in particular Sestrin1 and Sestrin2, is antagonized by amino acids, particularly leucine and, to a lesser extent, isoleucine, methionine and valine. In the presence of leucine, GATOR2 does not interact with Sestrin1 or Sestrin2 and mTORC1 is able to migrate to the lysosomal membrane where it is active. Sestrin1 and Sestrin2 directly bind leucine and to a lesser extent, isoleucine and methionine (Chantranupong et al., (2014) Cell Rep.; 9(1):1-8). The binding of leucine by Sestrin1 or -2 is required for disruption of its interaction with GATOR2 and subsequent activation of mTORC1. Sestrin2 mutants incapable of binding leucine cannot signal the presence of leucine to mTORC1, and cells depleted of Sestrin2 and its homologs render mTORC1 insensitive to the absence of leucine (Wolfson et al., (2015) Science pii: ab2674 [Epub ahead of print]).

The Sestrins are three related proteins (Sestrin1, -2 and -3) of poorly characterized molecular functions (Buckbinder et al., (1994) Proc Natl Acad Sci USA 91, 10640-10644; Budanov et al., (2002) Cell 134, 451-460; Peeters et al., (2003) Human genetics 112, 573-580). Sestrin2 inhibits mTORC1 signaling and has been proposed to activate AMPK upstream of TSC as well as interact with TSC (Budanov and Karin, (2008) Cell 134, 451-460), but later studies find inhibition of mTORC1 by Sestrin2 in the absence of AMPK (Peng et al., (2014) Cell 159(1): 122-33) further emphasizing the important role the GATOR2 complex plays in modulating mTORC1 in response to Sestrin2.

Modulation of the Sestrin-GATOR2 complex represents a potential therapeutic target for selectively modulating mTORC1 activity indirectly.

SUMMARY OF THE INVENTION

It has now been found that compounds of this invention, and pharmaceutically acceptable compositions thereof, are effective as Sestrin-GATOR2 modulators. Such compounds have the general formula I:

or a pharmaceutically acceptable salt thereof, wherein each variable is as defined and described herein.

Compounds of the present invention, and pharmaceutically acceptable compositions thereof, are useful for treating a variety of diseases, disorders or conditions, associated with mTORC1. Such diseases, disorders, or conditions include diabetes, epilepsy, neurodegeneration, immune response, suppressed skeletal muscle growth, and cellular proliferative disorders (e.g., cancer) such as those described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the study timeline for Example A. Male Sprague Dawley rats were acclimated to housing for 5 days and the dosing was on Day 0 as described in Table 6. Twenty-four hrs post-dose (day 1) the Female Urine Sniff Test (FUST) was conducted. On study day 2 (48 hrs post-dose), the Loctomotor Activity (LMA) assessment was conducted. The rats were fasted overnight for 20 hrs after which the Novelty-Suppressed Feeding Test (NSFT) was conducted (72 hrs post-dose).

FIG. 2 shows the effect of Ket and NV-5138 (1-90) in the FUST. All data are expressed as mean±SEM (n=8/treatment group). *p<0.05 and **p<0.01 indicate a significant difference by an unpaired two-tailed students t-test.

FIG. 3 shows the effect of Ket and NV-5138 (1-90) on the LMA assessment. Ketamine Vehicle (Sal); NV-5138 Vehicle (Veh); Ketamine (Ket); NV-5138 (NV). The number of breaks in the infrared beams over a 30 min period are shown. All data are expressed as mean±SEM (n=8/treatment group. No significant differences between groups were observed by an unpaired two-tailed students t-test.

FIG. 4 shows the effect of Ket and NV-5138 (1-90) in the Novelty-suppressed Feeding Test (NSFT). Ketamine Vehicle (Sal); NV-5138 Vehicle (Veh); Ketamine (Ket); NV-5138 (NV). The latency to feed in s is shown. All data are expressed as mean±SEM (n=8/treatment group). **p<0.01 indicates a significant difference by an unpaired two-tailed students t-test.

FIG. 5 shows the study timeline for Example B. Male Sprague Dawley rats were acclimated to housing for 5 days, the dosing was on Day 0 as described in Table 7. One-hour post-dose (day 0+1 hr) rats from Groups 1, 2, 3 and 4 were sacrificed followed by Prefrontal cortex (PFC) collection, synaptosome preparation, and WB analysis. Twenty-four hrs post-dose (day 1) rats from Groups 5, 6, 7 and 8 were sacrificed followed by PFC collection, synaptosome preparation, and WB analysis.

FIG. 6 shows a schematic representation of the PFC dissection of a rat brain. A) Dorsal view of a rat brain and the two black lines indicate location of the dissection to isolate the PFC region of the brain. B) Sagittal view of a rat brain, black diagonal line represents a cut to remove olfactory bulb and two black vertical lines represent cuts to isolate the PFC region.

FIG. 7 shows the effect of NV-5138 (1-90) and Ket on cellular pmTOR, pp70S6K, and p4E-BP1 levels in crude sunaptosomes prepared from PFC one hr post-dose administration. The fold-change of pmTOR (A), pp70S6K (B) and p4E-BP1 (C) (normalized to control Veh or Sal). Three representative WB out of a total of n=6 used for statistical analysis are shown above graphs for pmTOR (A), pp70S6K (B) and p4E-BP1 (C). All data are mean±SEM. *p<0.05, **p<0.01, ***p<0.001 indicate a significant difference by an unpaired two-tailed students t-test.

FIG. 8 shows the effect of Ket and NV-5138 (1-90) on GluR1, Synapsin 1, and PSD95 level in crude synaptosomes prepared from the PFC 24 hr post-dose administration. The fold-change of GluR1 (A), Synapsin 1 (B) and PSD95 (C) (normalized to respective control groups Sal or Veh) in crude synaptosomes purified from PFC. Three representative WB out of a total of n=6 used for statistical analysis are shown above graphs for GluR1 (A), Synapsin 1 (B) and PSD95 (C). All data are mean±SEM. *p<0.05 and **p<0.01 indicate a significant difference by an unpaired two-tailed students t-test.

FIG. 9 shows the timeline study for Example C. Male Sprague Dawley rats were acclimated to housing for 5 days, the dosing was on Day 0 as described in Table 8. One-hour post-dose (day 0+1 hr) rats from Groups 1 and, 2 were sacrificed, followed by the collection of plasma and dissected brain regions for determination of compound levels and WB analysis.

FIG. 10 shows the schematic representation of rat brain region dissected. Sagittal view of a rat brain, white arrow indicates region dissected for WB analysis.

FIG. 11 shows the effect of NV-5138 (1-90) on pS6 levels across multiple regions of the brain 1 hr post administration. Bar graph show fold-change of ^(S240/244)pS6 compared to Veh which was normalized to 1 in various regions of the rat brain. The representative WB used for the quantitative analysis are shown above the graph. All data are mean±SEM. *p<0.05 indicates a significant difference by an unpaired two-tailed students t-test.

FIG. 12 shows the timeline study for Example D. Male Sprague Dawley rats were acclimated to housing for 5 days, the dosing was on Day 0 as described in Table 9. One-hour post-dose (day 0+1 hr) rats from Groups 1, 2, and 3 were sacrificed for plasma, brain and peripheral tissues collection followed by processing for WB analysis.

FIG. 13 shows the effect of Leu and NV-5138 (1-90) on pS6 levels in brain and selected peripheral organs 1 hr following oral administration. Bar graph show fold-change of pS6 normalized to Veh in rat brain and peripheral tissues Gastrocnemius (Gastroc); Tibialis Anterior Muscle (TA); Epididymal fat (Epi Fat). Representative WB are shown above graphs. All data are mean±SEM (n=10/group). *p<0.05, **p<0.01, ***p<0.001, and ****p<0.0001 indicate a significant difference by an unpaired two-tailed students t-test.

FIG. 14 shows the timeline study for Example E. The dosing was on day 0, as described in Table 10. The Chronic Unpredictable Stree (CUS) procedure began on day minus 20 and ended on day 5 (Groups 3 and 4, n=14/group). Two groups of rats (Groups 1 and 2 n=14/group) were housed normally for 25 days and used as Non-Stressed (NS) groups. The first dose was on day 0. Twenty-four hours post-dose (day 1) the Sucrose Preference Test (SPT) was conducted following 6 hrs of water deprivation. The rats were then fasted overnight for 20 hrs after which the NSFT was conducted (48 hrs post-dose). A second dose of either Veh or NV-5138 was administered on day 5 followed by sacrifice 24 hrs later for brain collection, synaptosomes preparation and WB analysis.

FIG. 15 shows the schematic representation of PFC dissection of a rat brain. A) Dorsal view of a rat brain and the two black lines indicate location of the dissection to isolate the PFC region of the brain. B) Sagittal view of a rat brain, black diagonal line represents a cut to remove olfactory bulb and two black vertical lines represent cuts to isolate the PFC region.

FIG. 16 shows the body weight of NS and CUS rats on day minus 21 and day 0. Both NS and CUS rats were handled and weighed weekly. All data are mean±SEM (n=14/treatment group). ****p<0.0001 indicates a significant difference by two-way ANOVA followed by Tukey's multiple comparison test.

FIG. 17 shows the effect of NV-5138 (1-90) on the SPT in NS and CUS rats. Rats were treated with Veh or NV-5138 (160 mg/kg) at the end of the NS and CUS procedure on day 0 and the SPT was performed 24 hrs post-dose. The volume-ratio of 1% sucrose to water at the end of a 1 hr exposure is shown for all 4 groups (Preference). All data are mean±SEM (n=14/treatment group). *p<0.05 indicates a significant difference by two-way ANOVA followed by Tukey's multiple comparison test.

FIG. 18 shows the effect of NV-5138 (1-90) on the NSFT in NS and CUS rats. Rats were treated with Veh or NV-5138 at the end of the NS and CUS procedure and the NSFT was performed 48 hr post-dose. Bar graph shows latency to feed in NSFT. All data are shown as mean±SEM (n=14/treatment group). **p<0.01 and ****p<0.0001 indicate a significant difference by two-way ANOVA followed by Tukey's multiple comparison test.

FIG. 19 shows the effect of NV-5138 (1-90) on the expression of GluR1 and PSD95 in synaptosomes prepared from the PFC of NS and and CUS rats.

FIG. 20 shows the timeline study for Example F. Bilateral IT cannulas were implanted into the PFC of all rats, after 5 days acclimation, on day minus 14 followed by a 2-week recovery period. On day 0 test articles were administered as shown in Study design Table 11.

FIG. 21 shows the effect of mTORC1 inhibition in the PFC on the pharmacological efficacy of oral NV-5138 in the FST. Rats were administered Veh-R or R by IT followed 30 min later by an oral administration of Veh-NV-5138 or NV-5138 (160 mg/kg). The FST was performed 24 hrs following oral administration. All data are shown as mean±SEM (n=6-7/treatment group). ***p<0.001 and ****p<0.0001 indicate a significant difference by one-way ANOVA followed by Tukey's multiple comparison test.

FIG. 22 shows the effect of treatments using LMA assessment. Rats were administered Veh-R or R by IT followed 30 min later by an oral administration of Veh-NV-5138 or NV-5138 (1-90; 160 mg/kg). LMA was measured 48 hrs following oral administration. All data are shown as mean±SEM (n=6-7/treatment group). No significant differences were observed between groups by one-way ANOVA followed by Tukey's multiple comparison test.

FIG. 23 shows the effect of mTORC1 inhibition in the PFC on the pharmacological efficacy of oral NV-5138 (1-90). Rats were administered Veh-R or R by IT followed 30 min later by an oral administration of Veh-NV-5138 or NV-5138 (160 mg/kg). The NSFT was performed 72 hrs following oral administration following a 20 hrs fasting period. Bar graph shows NFST (A) and Food consumption (B). All data are shown as mean±SEM (n=6-7/treatment group). *p<0.05 indicates a significant difference by one-way ANOVA followed by Tukey's multiple comparison test.

FIG. 24 show the time study for behavioral tests of Example G. Male Sprague Dawley rats were all acclimated for 5 days post-shipment. On day 0 test articles were administered as shown in Study design Table 12. The FST was conducted on day 3 and day 7 and the NSFT was conducted on day 10 after a 20 hr overnight fast.

FIG. 25 shows the effect of Ket and NV-5138 (1-90) on the FST at 3 and 7 days post-dose. Bar graph show the FST performed at 3 and 7 days post-dose. Ketamine Vehicle (Sal); NV-5138 Vehicle (Veh); Ketamine (Ket); NV-5138 (NV). All data are shown as mean±SEM. *p<0.05 and **p<0.01 indicate a significant difference by an unpaired two-tailed students t-test.

FIG. 26 shows the effect of Ket and NV-5138 (1-90) on the NSFT at 10 days post-dose. Ketamine Vehicle (Sal); NV-5138 Vehicle (Veh); Ketamine (Ket); NV-5138 (NV). Bar graphs show the NSFT performed 10 days post-dose (A) and home cage food consumption (B) (Groups 3, 4, 5 and 6). All data are shown as mean±SEM. No significant differences were observed between groups by an unpaired two-tailed students t-test.

FIG. 27 shows the study timeline for Example H. Male Sprague Dawley rats were acclimated to housing for 5 days and the dosing was on Day 0 as described in Table 13. Twenty-four hrs post-dose (day 1) rats were sacrificed, brain slices prepared and EPSCs recorded. Fixed slices were then analyzed by microscopy for spine density and morphology.

FIG. 28 shows the frequency of 5-HT and hypocretin-induced EPSCs. Bar graph shows 5-hydroxytryptamine (5-HT)- and Hypocretin (Hcrt)-EPSCs in neurons 24 hrs after dosing recorded by whole cell patch clamp in PFC. The number of cells shown were derived from n=8 rats. All data are expressed as mean±SEM. **p<0.01 and ***p<0.001 indicate a significant difference by an unpaired two-tailed students t-test.

FIG. 29 shows the effect of NV-5138 (1-90) on dendrite morphopolgy. A) Representative two-photon images of high magnification Z-stack projections of distal, middle and proximal segments of apical tuft of neurobiotin-labeled layer V pyramidal cells 24 hr after dosing. B) Bar graph showing quantification of spine stubby, thin and mushroom per μm derived from n=9 cells/6-18 images/cell isolated from 4 and 5 animals for the vehicle and NV-5138 groups, respectively. All data are expressed as mean±SEM. *p<0.05 indicates a significant difference by an unpaired two-tailed students t-test.

FIG. 30 shows sample whole-cel lvoltage clamp traces of 5-HT- and Hcrt-induced EPSCs in slices from vehicle or NV-5138 (1-90) treated rats 24 hrs post-dose.

FIG. 31 shows the cumulative probability distribution of 5-HT- and Hcrt-induced EPSCs and the effect NV-5138 (1-90) on frequency but not amplitude.

FIG. 32 shows the study timeline for Example J. Male Sprague Dawley rats were acclimated to housing for 5 days. On day minus 1 rats were subjected to a pre-swim. Beginning on day 0, rats received Ket or Sal every other day for 7 days (day 0 to day 6), or NV-5138 once a day for 7 days (day 0 to day 6) as described in Table 14.

FIG. 33 shows the effect of Ket and NV-5138 (1-90) in the FST. NV-5138 Vehicle (Veh); Saline (Sal); Ketamine (Ket, 10 mg/kg), NV-5138 (“NV”; 40 or 80 mg/kg).

FIG. 34 shows the effect of Ket and NV-5138 (1-90) in the LMA. NV-5138 Vehicle (Veh); Saline (Sal); Ketamine (Ket, 10 mg/kg), NV-5138 (“NV”; 40 or 80 mg/kg).

FIG. 35 shows the effect of Ket and NV-5138 (1-90) in the NSFT and home cage feeding control. NV-5138 Vehicle (Veh); Saline (Sal); Ketamine (Ket, 10 mg/kg), NV-5138 (“NV”; 40 or 80 mg/kg).

FIG. 36 shows the effect of Ket (0.3 mg/kg) and NV-5138 (1-90; 160 mg/kg) as compared to chlordiazepoxide (1 mg/kg) in the Marmoset Human Threat Test. Data are expressed as mean±SEM (n=10/treatment group). ***P<0.001 with respect to the respective vehicle groups by one-way ANOVA followed by Dunnett test. * indicates there was emesis observed in 6 out of the 12 animals dosed in this group.

FIG. 37 shows the effect of Ket (0.3 mg/kg) and NV-5138 (1-90; 160 mg/kg) as compared to chlordiazepoxide (1 mg/kg) in the locomotor control of the Marmoset Human Threat Test. Data are expressed as mean±SEM (n=10/treatment group). ***P<0.001 with respect to the respective vehicle groups by one-way ANOVA followed by Dunnett test. * indicates there was emesis observed in 6 out of the 12 animals dosed in this group.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 1. General Description of Certain Embodiments of the Invention

Compounds of the present invention, and compositions thereof, are useful as Sestrin-GATOR2 modulators. In certain embodiments, the present invention provides a compound of formula I:

or a pharmaceutically acceptable salt thereof, wherein:

-   R¹ is H or C₁₋₆ alkyl; -   R² is R, —(CH₂)_(n)-phenyl, —C(O)R, —SO₂R, or —C(O)N(R)₂; -   n is 0, 1, or 2; -   each R is independently hydrogen, —CN, or an optionally substituted     group selected from saturated or unsaturated C₁₋₆ aliphatic, phenyl,     4-7 membered saturated or partially unsaturated monocyclic     carbocyclic ring, 5-6 membered monocyclic heteroaryl ring having 1-4     heteroatoms, or a 4-8 membered saturated or partially saturated     heterocyclic ring with 1-2 heteroatoms independently selected from     nitrogen, oxygen, or sulfur; -   R³ is Ring A, —C(O)R, —C(O)OR, —C(O)N(R)₂, —SO₃H, —SO₂N(R)₂, —S(O)R,     —S(O)Ring A, —OR or —B(OR)₂ where two OR groups on the same boron     are taken together with their intervening atoms to form a 5-8     membered monocyclic saturated or partially unsaturated, ring having     0-3 heteroatoms, in addition to the boron and two oxygens,     independently selected from nitrogen, oxygen, or sulfur, or R³ and     R⁴ taken together form an optionally substituted 5-6 membered ring     having 0-1 heteroatoms selected from nitrogen, oxygen or sulfur; -   L is a covalent bond or a straight or branched C₁₋₆ alkylene chain     optionally substituted with 1-9 fluoro groups; -   Ring A is an optionally substituted ring selected from phenyl or an     optionally substituted 5-6 membered heteroaryl ring having 1-4     heteroatoms independently selected from nitrogen, oxygen or sulfur; -   R⁴ is R, —CF₃, —OR, —N(R)₂, —Si(R)₃, or —SR, or R³ and R⁴ taken     together form an optionally substituted 5-6 membered ring having 0-1     heteroatoms selected from nitrogen, oxygen or sulfur; and -   R⁵ is H or C₁₋₄ alkyl.

2. Compounds and Definitions

Compounds of the present invention include those described generally herein, and are further illustrated by the classes, subclasses, and species disclosed herein. As used herein, the following definitions shall apply unless otherwise indicated. For purposes of this invention, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75^(th) Ed. Additionally, general principles of organic chemistry are described in “Organic Chemistry”, Thomas Sorrell, University Science Books, Sausalito: 1999, and “March's Advanced Organic Chemistry”, 5^(th) Ed., Ed.: Smith, M. B. and March, J., John Wiley & Sons, New York: 2001, the entire contents of which are hereby incorporated by reference.

The term “aliphatic” or “aliphatic group”, as used herein, means a straight-chain (i.e., unbranched) or branched, substituted or unsubstituted hydrocarbon chain that is completely saturated or that contains one or more units of unsaturation, or a monocyclic hydrocarbon or bicyclic hydrocarbon that is completely saturated or that contains one or more units of unsaturation, but which is not aromatic (also referred to herein as “carbocycle,” “cycloaliphatic” or “cycloalkyl”), that has a single point of attachment to the rest of the molecule. Unless otherwise specified, aliphatic groups contain 1-6 aliphatic carbon atoms. In some embodiments, aliphatic groups contain 1-5 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-4 aliphatic carbon atoms. In still other embodiments, aliphatic groups contain 1-3 aliphatic carbon atoms, and in yet other embodiments, aliphatic groups contain 1-2 aliphatic carbon atoms. In some embodiments, “cycloaliphatic” (or “carbocycle” or “cycloalkyl”) refers to a monocyclic C₃-C₆ hydrocarbon that is completely saturated or that contains one or more units of unsaturation, but which is not aromatic, that has a single point of attachment to the rest of the molecule. Suitable aliphatic groups include, but are not limited to, linear or branched, substituted or unsubstituted alkyl, alkenyl, alkynyl groups and hybrids thereof such as (cycloalkyl)alkyl, (cycloalkenyl)alkyl or (cycloalkyl)alkenyl.

The term “heteroatom” means one or more of oxygen, sulfur, nitrogen, phosphorus, or silicon (including, any oxidized form of nitrogen, sulfur, phosphorus, or silicon; the quaternized form of any basic nitrogen or; a substitutable nitrogen of a heterocyclic ring, for example N (as in 3,4-dihydro-2H-pyrrolyl), NH (as in pyrrolidinyl) or NR⁺ (as in N-substituted pyrrolidinyl)).

The term “unsaturated,” as used herein, means that a moiety has one or more units of unsaturation.

As used herein, the term “bivalent C₁₋₈ (or C₁₋₆) saturated or unsaturated, straight or branched, hydrocarbon chain”, refers to bivalent alkylene, alkenylene, and alkynylene chains that are straight or branched as defined herein.

The term “alkylene” refers to a bivalent alkyl group. An “alkylene chain” is a polymethylene group, i.e., —(CH₂)_(n)—, wherein n is a positive integer, preferably from 1 to 6, from 1 to 4, from 1 to 3, from 1 to 2, or from 2 to 3. A substituted alkylene chain is a polymethylene group in which one or more methylene hydrogen atoms are replaced with a substituent. Suitable substituents include those described below for a substituted aliphatic group.

The term “alkenylene” refers to a bivalent alkenyl group. A substituted alkenylene chain is a polymethylene group containing at least one double bond in which one or more hydrogen atoms are replaced with a substituent. Suitable substituents include those described below for a substituted aliphatic group.

The term “halogen” means F, Cl, Br, or I.

The term “aryl” used alone or as part of a larger moiety as in “aralkyl,” “aralkoxy,” or “aryloxyalkyl,” refers to monocyclic or bicyclic ring systems having a total of five to fourteen ring members, wherein at least one ring in the system is aromatic and wherein each ring in the system contains 3 to 7 ring members. The term “aryl” may be used interchangeably with the term “aryl ring.” In certain embodiments of the present invention, “aryl” refers to an aromatic ring system which includes, but not limited to, phenyl, biphenyl, naphthyl, anthracyl and the like, which may bear one or more substituents. Also included within the scope of the term “aryl,” as it is used herein, is a group in which an aromatic ring is fused to one or more non-aromatic rings, such as indanyl, phthalimidyl, naphthimidyl, phenanthridinyl, or tetrahydronaphthyl, and the like.

The terms “heteroaryl” and “heteroar-,” used alone or as part of a larger moiety, e.g., “heteroaralkyl,” or “heteroaralkoxy,” refer to groups having 5 to 10 ring atoms, preferably 5, 6, or 9 ring atoms; having 6, 10, or 14 n electrons shared in a cyclic array; and having, in addition to carbon atoms, from one to five heteroatoms. The term “heteroatom” refers to nitrogen, oxygen, or sulfur, and includes any oxidized form of nitrogen or sulfur, and any quatemized form of a basic nitrogen. Heteroaryl groups include, without limitation, thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, thiadiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolizinyl, purinyl, naphthyridinyl, and pteridinyl. The terms “heteroaryl” and “heteroar-”, as used herein, also include groups in which a heteroaromatic ring is fused to one or more aryl, cycloaliphatic, or heterocyclyl rings, where the radical or point of attachment is on the heteroaromatic ring. Nonlimiting examples include indolyl, isoindolyl, benzothienyl, benzofuranyl, dibenzofuranyl, indazolyl, benzimidazolyl, benzthiazolyl, quinolyl, isoquinolyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, AH quinolizinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, and pyrido[2,3-b]-1,4-oxazin-3(4H)-one. A heteroaryl group may be mono- or bicyclic. The term “heteroaryl” may be used interchangeably with the terms “heteroaryl ring,” “heteroaryl group,” or “heteroaromatic,” any of which terms include rings that are optionally substituted. The term “heteroaralkyl” refers to an alkyl group substituted by a heteroaryl, wherein the alkyl and heteroaryl portions independently are optionally substituted.

As used herein, the terms “heterocycle,” “heterocyclyl,” “heterocyclic radical,” and “heterocyclic ring” are used interchangeably and refer to a stable 5- to 7-membered monocyclic or 7-10-membered bicyclic heterocyclic moiety that is either saturated or partially unsaturated, and having, in addition to carbon atoms, one or more, preferably one to four, heteroatoms, as defined above. When used in reference to a ring atom of a heterocycle, the term “nitrogen” includes a substituted nitrogen. As an example, in a saturated or partially unsaturated ring having 0-3 heteroatoms selected from oxygen, sulfur or nitrogen, the nitrogen may be N (as in 3,4-dihydro-2H-pyrrolyl), NH (as in pyrrolidinyl), or ⁺NR (as in N substituted pyrrolidinyl).

A heterocyclic ring can be attached to its pendant group at any heteroatom or carbon atom that results in a stable structure and any of the ring atoms can be optionally substituted. Examples of such saturated or partially unsaturated heterocyclic radicals include, without limitation, tetrahydrofuranyl, tetrahydrothiophenyl pyrrolidinyl, piperidinyl, pyrrolinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, decahydroquinolinyl, oxazolidinyl, piperazinyl, dioxanyl, dioxolanyl, diazepinyl, oxazepinyl, thiazepinyl, morpholinyl, and quinuclidinyl. The terms “heterocycle,” “heterocyclyl,” “heterocyclyl ring,” “heterocyclic group,” “heterocyclic moiety,” and “heterocyclic radical,” are used interchangeably herein, and also include groups in which a heterocyclyl ring is fused to one or more aryl, heteroaryl, or cycloaliphatic rings, such as indolinyl, 3H indolyl, chromanyl, phenanthridinyl, or tetrahydroquinolinyl. A heterocyclyl group may be mono- or bicyclic. The term “heterocyclylalkyl” refers to an alkyl group substituted by a heterocyclyl, wherein the alkyl and heterocyclyl portions independently are optionally substituted.

As used herein, the term “partially unsaturated” refers to a ring moiety that includes at least one double or triple bond. The term “partially unsaturated” is intended to encompass rings having multiple sites of unsaturation, but is not intended to include aryl or heteroaryl moieties, as herein defined.

As described herein, compounds of the invention may contain “optionally substituted” moieties. In general, the term “substituted,” whether preceded by the term “optionally” or not, means that one or more hydrogens of the designated moiety are replaced with a suitable substituent. Unless otherwise indicated, an “optionally substituted” group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent selected from a specified group, the substituent may be either the same or different at every position. Combinations of substituents envisioned by this invention are preferably those that result in the formation of stable or chemically feasible compounds. The term “stable,” as used herein, refers to compounds that are not substantially altered when subjected to conditions to allow for their production, detection, and, in certain embodiments, their recovery, purification, and use for one or more of the purposes disclosed herein.

Suitable monovalent substituents on a substitutable carbon atom of an “optionally substituted” group are independently halogen; —(CH₂)₀₋₄R^(∘); —(CH₂)₀₋₄OR^(∘); —O(CH₂)₀₋₄R^(∘), —O—(CH₂)₀₋₄C(O)OR^(∘); —(CH₂)₀₋₄CH(OR^(∘))₂; —(CH₂)₀₋₄SR^(∘); —(CH₂)₀₋₄Ph, which may be substituted with R^(∘); —(CH₂)₀₋₄O(CH₂)_(0_1)Ph which may be substituted with R^(∘); —CH═CHPh, which may be substituted with R^(∘); —(CH₂)₀₋₄O(CH₂)₀₋₁-pyridyl which may be substituted with R^(∘); —NO₂; —CN; —N₃; —(CH₂)₀₋₄N(R^(∘))₂; —(CH₂)₀₋₄N(R^(∘))C(O)R^(∘); —N(R^(∘))C(S)R^(∘); —(CH₂)₀₋₄N(R^(∘))C(O)NR^(∘) ₂; —N(R^(∘))C(S)NR^(∘) ₂; —(CH₂)₀₋₄N(R^(∘))C(O)OR^(∘); —N(R^(∘))N(R^(∘))C(O)R^(∘); —N(R^(∘))N(R^(∘))C(O)NR^(∘) ₂; —N(R^(∘))N(R^(∘))C(O)OR^(∘); —(CH₂)₀₋₄C(O)R^(∘); —C(S)R^(∘); —(CH₂)₀₋₄C(O)OR^(∘); —(CH₂)₀₋₄C(O)SR^(∘); —(CH₂)₀₋₄C(O)OSiR^(∘) ₃; —(CH₂)₀₋₄OC(O)R^(∘); —OC(O)(CH₂)₀₋₄SR—, SC(S)SR^(∘); —(CH₂)₀₋₄SC(O)R^(∘); —(CH₂)₀₋₄C(O)NR^(∘) ₂; —C(S)NR^(∘) ₂; —C(S)SR^(∘); —SC(S)SR^(∘), —(CH₂)₀₋₄OC(O)NR^(∘) ₂; —C(O)N(OR^(∘))R^(∘); —C(O)C(O)R^(∘); —C(O)CH₂C(O)R^(∘); —C(NOR^(∘))R^(∘); —(CH₂)₀₋₄SSR^(∘); —(CH₂)₀₋₂S(O)₂R^(∘); —(CH₂)₀₋₄S(O)₂OR^(∘); —(CH₂)₀₋₄OS(O)₂R^(∘); —S(O)₂NR^(∘) ₂; —(CH₂)₀₋₄S(O)R^(∘); —N(R^(∘))S(O)₂NR^(∘) ₂; —N(R^(∘))S(O)₂R^(∘); —N(OR^(∘))R^(∘); —C(NH)NR^(∘) ₂; —P(O)₂R^(∘); —P(O)R^(∘) ₂; —OP(O)R^(∘) ₂; —OP(O)(OR^(∘))₂; —SiR^(∘) ₃; —(C₁₋₄ straight or branched alkylene)O—N(R^(∘))₂; or —(C₁₋₄ straight or branched alkylene)C(O)O—N(R^(∘))₂, wherein each R^(∘) may be substituted as defined below and is independently hydrogen, C₁₋₆ aliphatic, —CH₂Ph, —O(CH₂)₀₋₁Ph, —CH₂-(5-6 membered heteroaryl ring), or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the definition above, two independent occurrences of R^(∘), taken together with their intervening atom(s), form a 3-12-membered saturated, partially unsaturated, or aryl mono- or bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, which may be substituted as defined below.

Suitable monovalent substituents on R^(∘) (or the ring formed by taking two independent occurrences of R^(∘) together with their intervening atoms), are independently halogen, —(CH₂)₀₋₂R^(●), -(haloR^(●)), —(CH₂)₀₋₂OH, —(CH₂)₀₋₂OR^(●), —(CH₂)₀₋₂CH(OR*)₂; —O(haloR^(●)), —CN, —N₃, —(CH₂)₀₋₂C(O)R^(●), —(CH₂)₀₋₂C(O)OH, —(CH₂)₀₋₂C(O)OR^(●), —(CH₂)₀₋₂SR^(●), —(CH₂)₀₋₂SH, —(CH₂)₀₋₂NH₂, —(CH₂)₀₋₂NHR^(●), —(CH₂)₀₋₂NR*₂, —NO₂, —SiR*₃, —OSiR*₃, —C(O)SR^(●). —(C₁₋₄ straight or branched alkylene)C(O)OR^(●), or —SSR^(●) wherein each R^(●) is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently selected from C₁₋₄ aliphatic, —CH₂Ph, —O(CH₂)₀₋₁Ph, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents on a saturated carbon atom of R^(∘) include ═O and ═S.

Suitable divalent substituents on a saturated carbon atom of an “optionally substituted” group include the following: ═O, ═S, ═NNR*₂, ═NNHC(O)R*, ═NNHC(O)OR*, ═NNHS(O)₂R*, ═NR*, ═NOR*, —O(C(R*₂))₂₋₃O—, or —S(C(R*₂))₂₋₃S—, wherein each independent occurrence of R* is selected from hydrogen, C₁₋₆ aliphatic which may be substituted as defined below, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents that are bound to vicinal substitutable carbons of an “optionally substituted” group include: —O(CR*₂)₂₋₃O—, wherein each independent occurrence of R* is selected from hydrogen, C₁₋₆ aliphatic which may be substituted as defined below, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

Suitable substituents on the aliphatic group of R* include halogen, R^(●), -(haloR^(●)), —OH, —OR^(●), —O(haloR^(●)), —CN, —C(O)OH, —C(O)OR^(●), —NH₂, NHR^(●), —NR^(●) ₂, or —NO₂, wherein each R^(●) is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently C₁₋₄ aliphatic, —CH₂Ph, —O(CH₂)₀₋₁Ph, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

Suitable substituents on a substitutable nitrogen of an “optionally substituted” group include —R^(†), —NR^(†) ₂, —C(O)R^(†), —C(O)OR^(†), —C(O)C(O)R^(†), —C(O)CH₂C(O)R^(†), —S(O)₂R^(†), —S(O)₂NR^(†) ₂, —C(S)NR^(†) ₂, —C(NH)NR^(†) ₂, or —N(R^(†))S(O)₂R^(†); wherein each R^(†) is independently hydrogen, C₁₋₆ aliphatic which may be substituted as defined below, unsubstituted —OPh, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the definition above, two independent occurrences of R^(1′), taken together with their intervening atom(s) form an unsubstituted 3-12-membered saturated, partially unsaturated, or aryl mono- or bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

Suitable substituents on the aliphatic group of R^(†) are independently halogen, R^(●), -(haloR^(●)), —OH, —OR^(●), —O(haloR^(●)), —CN, —C(O)OH, —C(O)OR^(●), —NH₂, —NHR^(●), —NR^(†) ₂, or —NO₂, wherein each R^(†) is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently C₁₋₄ aliphatic, —CH₂Ph, —O(CH₂)₀₋₁Ph, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

As used herein, the term “pharmaceutically acceptable salt” refers to those salts which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit/risk ratio. Pharmaceutically acceptable salts are well known in the art. For example, S. M. Berge et al., describe pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 1977, 66, 1-19, incorporated herein by reference. Pharmaceutically acceptable salts of the compounds of this invention include those derived from suitable inorganic and organic acids and bases. Examples of pharmaceutically acceptable, nontoxic acid addition salts are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid or with organic acids such as acetic acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid or malonic acid or by using other methods used in the art such as ion exchange. Other pharmaceutically acceptable salts include adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecyl sulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and the like.

Salts derived from appropriate bases include alkali metal, alkaline earth metal, ammonium and N⁺(C₁₋₂alkyl)₄ salts. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. Further pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, loweralkyl sulfonate and aryl sulfonate.

Unless otherwise stated, structures depicted herein are also meant to include all isomeric (e.g., enantiomeric, diastereomeric, and geometric (or conformational)) forms of the structure; for example, the R and S configurations for each asymmetric center, Z and E double bond isomers, and Z and E conformational isomers. Therefore, single stereochemical isomers as well as enantiomeric, diastereomeric, and geometric (or conformational) mixtures of the present compounds are within the scope of the invention. Unless otherwise stated, all tautomeric forms of the compounds of the invention are within the scope of the invention. Additionally, unless otherwise stated, structures depicted herein are also meant to include compounds that differ only in the presence of one or more isotopically enriched atoms. For example, compounds having the present structures including the replacement of hydrogen by deuterium or tritium, or the replacement of a carbon by a ¹³C- or ¹⁴C-enriched carbon are within the scope of this invention. Such compounds are useful, for example, as analytical tools, as probes in biological assays, or as therapeutic agents in accordance with the present invention.

As used herein, the term “leucine mimetic” is defined as a compound that reduces the amount of Sestrin2 bound to GATOR2 by at least about 40% at 25 μM relative to leucine. In certain embodiments, the “leucine mimetic” reduces the amount of Sestrin2 bound to GATOR2 by at least about 100%, by at least about 150%, or by at least about 200%.

As used herein, the term “leucine antagonist” is defined as a compound that increases the amount of Sestrin2 bound to GATOR2 by at least about 40% at 25 μM relative to leucine (represented as −40% of leucine activity). In certain embodiments, the “leucine antagonist” increases the amount of Sestrin2 bound to GATOR2 by at least about 100%, by at least about 150%, or by at least about 200%.

The terms “measurable affinity” and “measurably inhibit,” as used herein, means a measurable change in Sestrin2 binding to GATOR2 between a sample comprising a compound of the present invention, or composition thereof, and Sestrin2, GATOR2 and leucine, and an equivalent sample comprising Sestrin2, GATOR2 and leucine, in the absence of said compound, or composition thereof.

3. Description of Exemplary Embodiments

In certain embodiments, the present invention provides a compound of formula I:

or a pharmaceutically acceptable salt thereof, wherein:

-   R¹ is H or C₁₋₆ alkyl; -   R² is R, —(CH₂)n-phenyl, —C(O)R, —SO₂R, or —C(O)N(R)₂; -   n is 0, 1, or 2; -   each R is independently hydrogen, —CN, or an optionally substituted     group selected from saturated or unsaturated C₁₋₆ aliphatic, phenyl,     4-7 membered saturated or partially unsaturated monocyclic     carbocyclic ring, 5-6 membered monocyclic heteroaryl ring having 1-4     heteroatoms, or a 4-8 membered saturated or partially saturated     heterocyclic ring with 1-2 heteroatoms independently selected from     nitrogen, oxygen, or sulfur; -   R³ is Ring A, —C(O)R, —C(O)OR, —C(O)N(R)₂, —SO₃H, —SO₂N(R)₂, —S(O)R,     —S(O)Ring A, —OR or —B(OR)₂ where two OR groups on the same boron     are taken together with their intervening atoms to form a 5-8     membered monocyclic saturated or partially unsaturated, ring having     0-3 heteroatoms, in addition to the boron and two oxygens,     independently selected from nitrogen, oxygen, or sulfur, or R³ and     R⁴ taken together form an optionally substituted 5-6 membered ring     having 0-1 heteroatoms selected from nitrogen, oxygen or sulfur; -   L is a covalent bond or a straight or branched C₁₋₆ alkylene chain     optionally substituted with 1-9 fluoro groups; -   Ring A is an optionally substituted ring selected from phenyl or an     optionally substituted 5-6 membered heteroaryl ring having 1-4     heteroatoms independently selected from nitrogen, oxygen or sulfur; -   R⁴ is R, —CF₃, —OR, —N(R)₂, —Si(R)₃, or —SR, or R³ and R⁴ taken     together form an optionally substituted 5-6 membered ring having 0-1     heteroatoms selected from nitrogen, oxygen or sulfur; and -   R⁵ is H or C₁₋₄ alkyl.

In some embodiments, a provided compound of formula I is other than those compounds depicted in Table 2, below.

As defined generally above, R¹ is H or C₁₋₆ alkyl. In some embodiments, R¹ is H. In other embodiments, R¹ is C₁₋₆ alkyl. In some embodiments R¹ is methyl. In some embodiments R¹ is isobutyl. In some embodiments, R¹ is selected from those depicted in Table 1, below. In some embodiments, R¹ is selected from those depicted in Table 2, below.

As defined generally above, R² is R, —(CH₂)_(n)-phenyl, —C(O)R, —SO₂R, or —C(O)N(R)₂. In some embodiments, R² is R. In some embodiments, R² is —(CH₂)_(n)-phenyl. In some embodiments, R² is —C(O)R. In some embodiments, R² is —SO₂R. In some embodiments, R² is —C(O)N(R)₂. In some embodiments, R² is methyl. In some embodiments, R² is —(CH₂)-phenyl. In some embodiments, R² is —C(O)CH₃. In some embodiments, R² is selected from those depicted in Table 1, below. In some embodiments, R² is selected from those depicted in Table 2, below.

As defined generally above, n is 0, 1, or 2. In some embodiments, n is 0. In some embodiments, n is 1. In some embodiments, n is 2.

As defined generally above, R³ is Ring A, —C(O)R, —C(O)OR, —C(O)N(R)₂, —SO₃H, —SO₂N(R)₂, —S(O)R, —S(O)Ring A, —OR or —B(OR)₂ where two —OR groups on the same boron are taken together with their intervening atoms to form a 5-8 membered monocyclic saturated or partially unsaturated, ring having 0-3 heteroatoms, in addition to the boron and two oxygens, independently selected from nitrogen, oxygen, or sulfur, or R³ and R⁴ taken together form an optionally substituted 5-6 membered ring having 0-1 heteroatoms selected from nitrogen, oxygen or sulfur.

In some embodiments, R³ is —C(O)OH. In some embodiments, R³ is —C(O)N(R)₂. In some embodiments, R³ is —SO₃H. In some embodiments, R³ is —SO₂N(R)₂. In some embodiments, R³ is —B(OR)₂ where two —OR groups on the same boron are taken together with their intervening atoms to form a 5-8 membered monocyclic saturated, partially unsaturated, or heterocyclic ring having 0-3 heteroatoms, in addition to the boron and two oxygens, independently selected from nitrogen, oxygen, or sulfur. In some embodiments, R³ and R⁴ taken together form an optionally substituted 5-6 membered ring having 0-1 heteroatoms selected from nitrogen, oxygen or sulfur.

In some embodiments, R³ is Ring A. As defined generally above, Ring A is an optionally substituted ring selected from phenyl or an optionally substituted 5-6 membered heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen or sulfur. In some embodiments, Ring A is optionally substituted phenyl. In some embodiments, Ring A is an optionally substituted 5-membered heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen or sulfur. In some embodiments, Ring A is an optionally substituted 5-membered heteroaryl ring selected from imidazolyl, isoxazolyl, 1H-pyrrolyl (e.g., maleimido), pyrazolyl, oxazolyl, tetrazolyl, thiazolyl and triazolyl. In some embodiments, Ring A is an optionally substituted 6-membered heteroaryl ring having 1-2 nitrogen atoms. In some embodiments, Ring A is an optionally substituted 6-membered ring selected from pyridyl and pyrimidinyl. In some embodiments, Ring A is selected from those depicted in Table 1, below.

In some embodiments, R³ is (pinacolato)boron. In some embodiments, R³ is selected from those depicted in Table 1, below. In some embodiments, R³ is selected from those depicted in Table 2, below.

As defined generally above, L is a covalent bond or a straight or branched C₁₋₆ alkylene chain optionally substituted with 1-4 fluoro groups. In some embodiments, L is a covalent bond. In some embodiments, Lisa straight or branched C₁₋₆ alkylene chain optionally substituted with 1-4 fluoro groups. In some embodiments, L is methylene. In some embodiments, L is n-butylenyl. In some embodiments, L is ethylenyl. In some embodiments, L is n-propylenyl. In some embodiments, L is selected from those depicted in Table 1, below. In some embodiments, L is selected from those depicted in Table 2, below.

In some embodiments, Lisa branched C₁₋₆ alkylene chain optionally substituted with 1-4 fluoro groups. In certain embodiments, L is —C(CH₃)₂—. In other embodiments, L is —C(CH₃)(CF₃)—.

As defined generally above, R⁴ is R, —CF₃, —OR, —N(R)₂, —Si(R)₃ or —SR, or R³ and R⁴ taken together form an optionally substituted 5-6 membered ring having 0-1 heteroatoms selected from nitrogen, oxygen or sulfur. In some embodiments, R⁴ is R. In some embodiments, R⁴ is —CF₃. In some embodiments, R⁴ is —OR. In some embodiments, R⁴ is —N(R)₂. In some embodiments, R⁴ is —Si(R)₃. In some embodiments, R⁴ is —SR. In some embodiments, R⁴ is isopropyl. In some embodiments, R⁴ is tert-butyl. In some embodiments, R⁴ is cyclopropyl. In some embodiments, R⁴ is cyclobutyl. In some embodiments, R⁴ is sec-butyl. In some embodiments, R⁴ is methoxyl. In some embodiments, R⁴ is methylthioyl. In some embodiments, R³ and R⁴ taken together form an optionally substituted 5-6 membered ring having 0-1 heteroatoms selected from nitrogen, oxygen or sulfur. In some embodiments, R⁴ is selected from those depicted in Table 1, below. In some embodiments, R⁴ is selected from those depicted in Table 2, below.

As defined generally above, R⁵ is H or C₁₋₄ alkyl. In some embodiments, R⁵ is H. In some embodiments, R⁵ is C₁₋₄ alkyl. In some embodiments, R⁵ is methyl. In some embodiments, R⁵ is selected from those depicted in Table 1, below. In some embodiments, R⁵ is selected from those depicted in Table 2, below.

In certain embodiments, the present invention provides for a compound of formula II:

or a pharmaceutically acceptable salt thereof, wherein each variable is as defined above and as described in embodiments provided herein, both singly and in combination.

In certain embodiments, the present invention provides for a compound of formula III:

or a pharmaceutically acceptable salt thereof, wherein:

-   Q is —C(R′)₂— or —NH—; -   each of R^(x) and R^(y) is hydrogen, or R^(x) and R^(y) taken     together form ═O; -   is a double bond or a single bond; -   each R is independently hydrogen, —CN, or an optionally substituted     group selected from C₁₋₆ aliphatic, phenyl, 4-7 membered saturated     or partially unsaturated monocyclic carbocyclic ring, 5-6 membered     monocyclic heteroaryl ring having 1-4 heteroatoms, or a 4-8 membered     saturated or partially saturated heterocyclic ring with 1-2     heteroatoms independently selected from nitrogen, oxygen, or sulfur; -   each R′ is independently hydrogen, halogen, —CN, or an optionally     substituted group selected from C₁₋₆ aliphatic, phenyl, 4-7 membered     saturated or partially unsaturated monocyclic carbocyclic ring, 5-6     membered monocyclic heteroaryl ring having 1-4 heteroatoms, or a 4-8     membered saturated or partially saturated heterocyclic ring with 1-2     heteroatoms independently selected from nitrogen, oxygen, or sulfur; -   L is a covalent bond or a straight or branched C₁₋₆ alkylene chain     optionally substituted with 1-9 fluoro groups; -   R^(4′) is R, —CF₃, —OR, —N(R)₂, —Si(R)₃, or —SR; and -   R⁵ is H, —OR, or C₁₋₄ alkyl.

In some embodiments, Q is —NH—. In some embodiments, Q is —CH₂—. In some embodiments, Q is —CHF—.

In some embodiments, L is —CH₂—.

In some embodiments, each R^(x) and R^(y) is hydrogen. In some embodiments, R^(x) and R^(y) taken together form ═O.

In some embodiments, R⁵ is H. In some embodiments, R⁵ is —OH.

In some embodiments,

is a single bond. In some embodiments,

is a double bond.

In certain embodiments, the present invention provides for a compound of formulae IV-a, IV-b, or IV-c:

or a pharmaceutically acceptable salt thereof, wherein:

-   R¹ is H or C₁₋₆ alkyl; -   R² is R, —(CH₂)_(n)-phenyl, —C(O)R, —SO₂R, or —C(O)N(R)₂; -   each R⁴ is independently R, halogen, or —CF₃; -   each R is independently hydrogen, —CN, or an optionally substituted     group selected from saturated or unsaturated C₁₋₆ aliphatic, phenyl,     4-7 membered saturated or partially unsaturated monocyclic     carbocyclic ring, 5-6 membered monocyclic heteroaryl ring having 1-4     heteroatoms, or a 4-8 membered saturated or partially saturated     heterocyclic ring with 1-2 heteroatoms independently selected from     nitrogen, oxygen, or sulfur; and -   L¹ is a covalent bond or a straight or branched C₁₋₆ alkylene chain     optionally substituted with 1-9 fluoro groups.

In some embodiments, R¹ is H. In some embodiments, R¹ is C₁₋₆ alkyl.

In some embodiments, R¹ is selected from those depicted in Table 1, below.

In some embodiments, R² is R. In some embodiments, R² is —(CH₂)_(n)-phenyl. In some embodiments, R² is —C(O)R.

In some embodiments, R² is selected from those depicted in Table 1, below.

In some embodiments, each R^(4″) is independently R, halogen, or —CF₃. In some embodiments, R^(4″) is R. In some embodiments, R^(4″) is halogen. In some embodiments, R^(4″) is —CF₃. In some embodiments, R^(4″) is selected from those depicted in Table 1, below.

In some embodiments, L¹ is a covalent bond or a straight or branched C₁₋₆ alkylene chain optionally substituted with 1-9 fluoro groups. In some embodiments, L¹ is a covalent bond. In some embodiments, L¹ is a straight or branched C₁₋₆ alkylene chain optionally substituted with 1-9 fluoro groups. In some embodiments, L¹ is selected from those depicted in Table 1, below.

Exemplary compounds of the present invention are set forth in Table 1, below. Table 1. Exemplary Compounds

TABLE 1 Exemplary Compounds

I-1

I-2

I-3

I-4

I-5

I-6

I-7

I-8

I-9

I-11

I-12

I-13

I-14

I-15

I-16

I-17

I-18

I-19

I-20

I-21

I-22

I-25

I-26

I-36

I-45

I-46

I-47

I-48

I-49

I-50

I-51

I-52

I-53

I-54

I-55

I-56

I-57

I-58

I-59

I-60

I-61

I-62

I-63

I-64

I-65

I-66

I-67

I-68

I-69

I-70

I-71

I-72

I-73

I-74

I-75

I-76

I-77

I-78

I-79

I-80

I-81

I-82

I-83

I-84

I-85

I-86

I-87

I-88

I-89

I-90

I-91

I-92

I-93

I-94

I-95

I-96

I-97

I-98

I-99

I-100

I-101

I-102

I-103

I-104

I-105

I-106

I-107

I-108

I-109

I-110

I-111

I-113

I-114

I-115

I-116

I-117

I-118

I-119

I-120

I-121

I-122

I-123

I-124

I-125

I-126

I-127

I-128

I-129

I-130

I-131

I-132

I-133

I-134

I-135

I-136

I-137

I-138

I-139

I-140

I-141

I-142

I-143

I-144

I-145

I-146

I-147

I-148

I-149

I-150

I-151

I-152

I-153

I-154

I-155

I-156

I-157

I-158

I-159

I-160

I-161

I-162

I-163

I-164

I-165

I-166

I-167

I-168

I-169

I-170

I-171

I-172

I-173

I-174

I-175

I-176

I-177

I-178

I-179

I-180

I-181

I-182

I-183

I-184

I-185

I-186

I-187

I-188

I-189

I-190

I-191

I-192

I-193

I-194

I-195

I-196

I-197

I-198

I-199

I-200

I-201

I-202

I-203

I-204

I-205

I-206

I-207

I-208

I-209

I-210

I-211

I-212

I-213

I-214

I-215

I-216

I-217

I-218

I-219

I-220

I-221

I-222

I-223

I-224

I-225

I-226

I-227

I-228

I-229

I-230

I-231

I-232

I-233

I-234

I-235

I-236

I-237

I-238

I-239

I-240

I-241

I-242

I-243

I-244

I-245

I-246

I-247

I-248

I-249

I-250

I-251

I-252

I-253

I-254

Exemplary compounds of the invention are set forth in Table 2, below.

TABLE 2 Exemplary Compounds

In some embodiments, the present invention provides a compound set forth in Table 1, above, or a pharmaceutically acceptable salt thereof. In some embodiments, the present invention provides a compound set forth in Table 2, above, or a pharmaceutically acceptable salt thereof.

4. Uses, Formulation and Administration

Pharmaceutically Acceptable Compositions

According to another embodiment, the invention provides a composition comprising a compound of this invention or a pharmaceutically acceptable derivative thereof and a pharmaceutically acceptable carrier, adjuvant, or vehicle. The amount of compound in compositions of this invention is such that is effective to measurably inhibit or activate the Sestrin-GATOR2 interaction, in a biological sample or in a patient. In certain embodiments, the amount of compound in compositions of this invention is such that is effective to measurably inhibit or activate the Sestrin-GATOR2 interaction, in a biological sample or in a patient. In certain embodiments, a composition of this invention is formulated for administration to a patient in need of such composition. In some embodiments, a composition of this invention is formulated for oral administration to a patient.

The term “patient,” as used herein, means an animal, preferably a mammal, and most preferably a human.

The term “pharmaceutically acceptable carrier, adjuvant, or vehicle” refers to a non-toxic carrier, adjuvant, or vehicle that does not destroy the pharmacological activity of the compound with which it is formulated. Pharmaceutically acceptable carriers, adjuvants or vehicles that may be used in the compositions of this invention include, but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins, such as human serum albumin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts or electrolytes, such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol, sodium carboxymethylcellulose, polyacrylates, waxes, polyethylene-polyoxypropylene-block polymers, polyethylene glycol and wool fat.

Compositions of the present invention may be administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir. The term “parenteral” as used herein includes subcutaneous, intravenous, intramuscular, intra-articular, intra-synovial, intrasternal, intrathecal, intrahepatic, intralesional and intracranial injection or infusion techniques. Preferably, the compositions are administered orally, intraperitoneally or intravenously. Sterile injectable forms of the compositions of this invention may be aqueous or oleaginous suspension. These suspensions may be formulated according to techniques known in the art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium.

For this purpose, any bland fixed oil may be employed including synthetic mono- or di-glycerides. Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation of injectables, as are natural pharmaceutically-acceptable oils, such as olive oil or castor oil, especially in their polyoxyethylated versions. These oil solutions or suspensions may also contain a long-chain alcohol diluent or dispersant, such as carboxymethyl cellulose or similar dispersing agents that are commonly used in the formulation of pharmaceutically acceptable dosage forms including emulsions and suspensions. Other commonly used surfactants, such as Tweens, Spans and other emulsifying agents or bioavailability enhancers which are commonly used in the manufacture of pharmaceutically acceptable solid, liquid, or other dosage forms may also be used for the purposes of formulation.

Pharmaceutically acceptable compositions of this invention may be orally administered in any orally acceptable dosage form including, but not limited to, capsules, tablets, aqueous suspensions or solutions. In the case of tablets for oral use, carriers commonly used include lactose and corn starch. Lubricating agents, such as magnesium stearate, are also typically added. For oral administration in a capsule form, useful diluents include lactose and dried cornstarch. When aqueous suspensions are required for oral use, the active ingredient is combined with emulsifying and suspending agents. If desired, certain sweetening, flavoring or coloring agents may also be added.

Alternatively, pharmaceutically acceptable compositions of this invention may be administered in the form of suppositories for rectal administration. These can be prepared by mixing the agent with a suitable non-irritating excipient that is solid at room temperature but liquid at rectal temperature and therefore will melt in the rectum to release the drug. Such materials include cocoa butter, beeswax and polyethylene glycols.

Pharmaceutically acceptable compositions of this invention may also be administered topically, especially when the target of treatment includes areas or organs readily accessible by topical application, including diseases of the eye, the skin, or the lower intestinal tract. Suitable topical formulations are readily prepared for each of these areas or organs.

Topical application for the lower intestinal tract can be effected in a rectal suppository formulation (see above) or in a suitable enema formulation. Topically-transdermal patches may also be used.

For topical applications, provided pharmaceutically acceptable compositions may be formulated in a suitable ointment containing the active component suspended or dissolved in one or more carriers. Carriers for topical administration of compounds of this invention include, but are not limited to, mineral oil, liquid petrolatum, white petrolatum, propylene glycol, polyoxyethylene, polyoxypropylene compound, emulsifying wax and water. Alternatively, provided pharmaceutically acceptable compositions can be formulated in a suitable lotion or cream containing the active components suspended or dissolved in one or more pharmaceutically acceptable carriers. Suitable carriers include, but are not limited to, mineral oil, sorbitan monostearate, polysorbate 60, cetyl esters wax, cetearyl alcohol, 2-octyldodecanol, benzyl alcohol and water.

For ophthalmic use, provided pharmaceutically acceptable compositions may be formulated as micronized suspensions in isotonic, pH adjusted sterile saline, or, preferably, as solutions in isotonic, pH adjusted sterile saline, either with or without a preservative such as benzylalkonium chloride. Alternatively, for ophthalmic uses, the pharmaceutically acceptable compositions may be formulated in an ointment such as petrolatum.

Pharmaceutically acceptable compositions of this invention may also be administered by nasal aerosol or inhalation. Such compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may be prepared as solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbons, and/or other conventional solubilizing or dispersing agents.

Most preferably, pharmaceutically acceptable compositions of this invention are formulated for oral administration. Such formulations may be administered with or without food. In some embodiments, pharmaceutically acceptable compositions of this invention are administered without food. In other embodiments, pharmaceutically acceptable compositions of this invention are administered with food.

The amount of compounds of the present invention that may be combined with the carrier materials to produce a composition in a single dosage form will vary depending upon the host treated, the particular mode of administration. Preferably, provided compositions should be formulated so that a dosage of between 0.01-100 mg/kg body weight/day of the inhibitor can be administered to a patient receiving these compositions.

It should also be understood that a specific dosage and treatment regimen for any particular patient will depend upon a variety of factors, including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, rate of excretion, drug combination, and the judgment of the treating physician and the severity of the particular disease being treated. The amount of a compound of the present invention in the composition will also depend upon the particular compound in the composition.

Uses of Compounds and Pharmaceutically Acceptable Compositions

Compounds and compositions described herein are generally useful for the inhibition or activation of the Sestrin-GATOR2 interaction. In some embodiments, a provided compound, or composition thereof, is an activator of the Sestrin-GATOR2 interaction.

The activity of a compound utilized in this invention as an inhibitor or activator of the Sestrin-GATOR2 interaction, may be assayed in vitro, in vivo or in a cell line. In vitro assays include assays that determine the inhibition or activation of the Sestrin-GATOR2 interaction. Alternate in vitro assays quantitate the ability of the inhibitor or activator to decrease or increase the binding of Sestrin to GATOR2. Detailed conditions for assaying a compound utilized in this invention as an inhibitor or activator of the Sestrin-GATOR2 interaction, are set forth in the Examples below.

As used herein, the terms “treatment,” “treat,” and “treating” refer to reversing, alleviating, delaying the onset of, or inhibiting the progress of a disease or disorder, or one or more symptoms thereof, as described herein. In some embodiments, treatment may be administered after one or more symptoms have developed. In other embodiments, treatment may be administered in the absence of symptoms. For example, treatment may be administered to a susceptible individual prior to the onset of symptoms (e.g., in light of a history of symptoms and/or in light of genetic or other susceptibility factors). Treatment may also be continued after symptoms have resolved, for example to prevent or delay their recurrence.

Provided compounds are inhibitors or activators of the Sestrin-GATOR2 interaction and are therefore useful for treating one or more disorders associated with activity of mTORC1. Thus, in certain embodiments, the present invention provides a method for treating an mTORC1-mediated disorder comprising the step of administering to a patient in need thereof a compound of the present invention, or pharmaceutically acceptable composition thereof.

As used herein, the terms “mTORC1-mediated” disorders, diseases, and/or conditions as used herein means any disease or other deleterious condition in which mTORC1, is known to play a role. Accordingly, another embodiment of the present invention relates to treating or lessening the severity of one or more diseases in which mTORC1 is known to play a role.

In some embodiments, the method of activating mTORC is used to treat or prevent depression. (See Ignácio et al., (2015) Br J Clin Pharmacol. November 27). Accordingly, in some embodiments, the present invention provides a method of treating or preventing depression, in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the depression is treatment-resistant depression (“TRD”). In some embodiments, the treatment resistant depression is resistant to first line treatments. In some embodiments, the treatment resistant depression is resistant to second line treatments.

In some embodiments, the present invention provides a method of treating depression in a patient in need thereof, wherein said patient experiences a 50% reduction in depression scale score. In some embodiments, the patient experiences a 50% reduction in depression scale score within fewer than six weeks of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within fewer than four weeks of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within two weeks of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within fewer than two weeks of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within one week of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within seven days of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within six days of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within five days of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within four days of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within three days of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within two days of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within one day of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the patient experiences a 50% reduction in depression scale score within twenty-four hours of administration of the compound or pharmaceutically acceptable composition. In some embodiments, the depression scale score is selected from the Montgomery-Asberg Depression Rating Scale (MADRS), the Hamilton Depression Rating Scale (HAMD-6), the Inventory of Depression Symptomatology Self-Rated Scale (IDS-SR), and the Clinical Global Impression Severity Scale (CGI-S).

In some embodiments, the present invention provides a method of treating depression in a patient in need thereof, comprising the step of orally administering to said patient a provided compound or pharmaceutically acceptable composition thereof, wherein the patient experiences a reduction in depression scale score comparable to ketamine administered via i.p. injection. In some embodiments, the reduction in depression scale score results from a single oral administration. In some embodiment, the reduction in depression scale score results from a plurality of oral administrations.

In some embodiments, the method of activating mTORC1 is used to elicit a rapid onset antidepressant activity. Accordingly, in some embodiments, the present invention provides a method of eliciting a rapid onset antidepressant activity, in a patient in need thereof suffering from TRD, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the rapid onset antidepressant activity occurs within two weeks of administration of said compound or composition. In some embodiments, the rapid onset antidepressant activity occurs within one week of administration of said compound or composition. In some embodiments, the rapid onset antidepressant activity occurs within seven days of administration of said compound or composition. In some embodiments, the rapid onset antidepressant activity occurs within six days of administration of said compound or composition. In some embodiments, the rapid onset antidepressant activity occurs within five days of administration of said compound or composition. In some embodiments, the rapid onset antidepressant activity occurs within four days of administration of said compound or composition. In some embodiments, the rapid onset antidepressant activity occurs within three days of administration of said compound or composition. In some embodiments, the rapid onset antidepressant activity occurs within two days of administration of said compound or composition. In some embodiments, the rapid onset antidepressant activity occurs within one day of administration of said compound or composition. In some embodiments, the rapid onset antidepressant activity occurs within less than twenty-four hours of administration of said compound or composition.

In some embodiments, the present invention provides a method of eliciting a long-lasting, sustained antidepressant activity, in a patient in need thereof suffering from depression, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the patient in need suffers from TRD. In some embodiments, the long-lasting, sustained antidepressant activity persists for at least twenty-four hours after a single administration of a provided compound or a pharmaceutically acceptable composition thereof. In some embodiments, the long-lasting, sustained antidepressant activity persists for longer than one day. In some embodiments, the long-lasting, sustained antidepressant activity persists for at least two days. In some embodiments, the long-lasting, sustained antidepressant activity persists for at least three days. In some embodiments, the long-lasting, sustained antidepressant activity persists for at least four days. In some embodiments, the long-lasting, sustained antidepressant activity persists for at least five days. In some embodiments, the long-lasting, sustained antidepressant activity persists for at least six days. In some embodiments, the long-lasting, sustained antidepressant activity persists for at least seven days.

In some embodiments, the present invention provides a method of eliciting antidepressant activity that is both rapid onset and long-lasting, sustained.

In some embodiments, the present invention provides a method of eliciting a positive behavioral response in a subject, comprising the step of administering to said subject a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the positive behavioral response correlates with an improvement in mood. In some embodiments, the positive behavioral response correlates with an reduction of anxiety. In some embodiments, the positive behavioral response corresponds with an improvement in mood. In some embodiments, the positive behavioral response correlates with an improved ability to cope with stress.

In some embodiments, the present invention provides a method of eliciting a rapid onset, positive behavioral response is a subject, comprising the step of administering to said subject a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the positive behavioral response occurs within twenty-four hours of administration. In some embodiments, the positive behavioral response occurs within one day of administration. In some embodiments, the positive behavioral response occurs within two days of administration. In some embodiments, the positive behavioral response occurs within three days of administration. In some embodiments, the positive behavioral response occurs within four days of administration. In some embodiments, the positive behavioral response occurs within five days of administration. In some embodiments, the positive behavioral response occurs within six days of administration. In some embodiments, the positive behavioral response occurs within seven days of administration. In some embodiments, the positive behavioral response occurs within one week of administration.

In some embodiments, the present invention provides a method of eliciting a long-lasting, sustained positive behavioral response in a subject, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the long-lasting, sustained positive behavioral response persists for longer than one day. In some embodiments, the long-lasting, sustained positive behavioral response persists for at least two days. In some embodiments, the long-lasting, sustained positive behavioral response persists for at least three days. In some embodiments, the long-lasting, sustained positive behavioral response persists for at least four days. In some embodiments, the long-lasting, sustained positive behavioral response persists for at least five days. In some embodiments, the long-lasting, sustained positive behavioral response persists for at least six days. In some embodiments, the long-lasting, sustained positive behavioral response persists for at least seven days.

In some embodiments, the present invention provides a method of eliciting a positive behavioral response that is both rapid onset and long-lasting, sustained.

In some embodiments, the present invention provides a method of ameliorating and/or reversing behavioral and synaptic defects caused by chronic, unpredictable stress (CUS), in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the method ameliorates and/or reverses behavioral defects caused by CUS. In some embodiments, the method ameliorates and/or reverses synaptic defects caused by CUS. In some embodiments, the synaptic defect caused by CUS is a decrease in postsynaptic protein expression. In some embodiments, the decrease in postsynaptic protein expression is a decrease in the expression of GLUR1 or PSD95.

In some embodiments, the method of activating mTORC1 is used to treat or prevent forms of autism. (See Novarino et al., (2012) Science 19 October, 338:6105, pp. 394-397). Accordingly, in some embodiments, the present invention provides a method of treating or preventing a form of autism, in a subject in need thereof, comprising the step of administering to said subject a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the autism is a genetic form of autism.

In some embodiments, the present invention provides a method of treating a genetic form of autism in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. SHANK3 haploinsufficiency is causative for the neurological features of Phelan-McDermid syndrome (PMDS), including a high risk of autism spectrum disorder (Bidinosti et al. (2016) Science Reports 351, 1199-1203). Down regulation of mTORC1 in SHANK3 deficient neurons is due to enhanced phosphorylation and activation of serine/threonine protein phosphatase 2A (PP2A) regulatory subunit, B56b, by its kinase, Cdc2-like kinase 2 (Bidinosti et al. (2016) Science Reports 351, 1199-1203). SHANK3 mutant mice show autistic traits (Yang et al. (2012) The Journal of Neuroscience 32, 6525-6541). Patients with autistic traits and motor delays carry deleterious homozygous mutations in the SLC7A5 gene. Solute carrier transporter 7a5 (SLC7A5), a large neutral amino acid transporter localized at the blood brain barrier (BBB), has an essential role in maintaining normal levels of brain BCAAs. Leucine intracerebroventricular administration ameliorates abnormal behaviors in adult mutant mice (Tarlungeanu et al. (2016) Cell 167, 1481-1494).

In some embodiments, the present invention provides a method of treating a Lysosomal Storage Disease or Disorder (“LSD”) in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. LSDs are a group of inherited metabolic disorders that result from defects in lysosomal function. Lysosomal storage disorders are caused by lysosomal dysfunction usually as a consequence of deficiency of a single enzyme required for the metabolism of lipids, glycoproteins (sugar containing proteins) or so-called mucopolysaccharides. In some embodiments, the present invention provides a method of treating a lipid storage disorder in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the lipid storage disorder is selected from a sphingolipidose (e.g., gangliosidosis, Gaucher, Niemann-Pick disease, or Metachromatic leukodystrophy). In some embodiments, the present invention provides a method of treating a gangliosidosis (e.g., Tay-Sachs disease or a leukodystrophy). In some embodiment, the present invention provides a method of treating a mucopolysaccharidoses in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the mucopolysaccharidoses is Hunter syndrome or Hurler disease.

In some embodiments, the present invention provides a method of treating JNCL (Batten Disease) in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. JNCL is caused by the deletion of exons 7 and 8 of the CLN3 gene resulting in a nonfunctional protein. Battenin, the full-length protein encoded by CLN3, is a transmembrane protein that localizes to the late endosome and lysosome where it has been shown to help regulate pH, amino acid balance and vesicle trafficking (Pearce et al. (1999) Nature Genetics 22, 1; Fossale et al. (2004) BMC Neuroscience 10, 5) mTOR activation requires intracellular nutrients provided by autophagy which, in in vitro and in vivo models of JNCL, are lowered due to the lack of functional battenin (Cao et al. (2006) Journal of Biological Chemistry 281, 29).

In some embodiments, the present invention provides a method of treating cystinosis in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. Cystinosis is an autosomal recessive disease affecting those with two alleles mutated in the CSTN gene; the lysosomal cystine transporter cystinosin is defective in efflux of cystine from the lysosome, resulting in cystine crystal formation in renal epithelial tubules and loss of kidney function. Studies have shown defective or reduced mTORC1 signaling in cells lacking CSTN and mislocalized mTOR (Ivanova et al. (2016) J Inherit Metab Dis. 39(3), 457-64; Andrzejewska et al. (2016) J Am Soc Nephrol. 27(6), 1678-1688e). These defects could not be rescued by cysteamine (Ivanova et al. (2016) J Inherit Metab Dis. 39(3), 457-64; Andrzejewska et al. (2016) J Am Soc Nephrol. 27(6), 1678-1688e). Cystinosin has also been found to bind mTORC1 pathway components v-ATPase, Rags, and Ragulator (Andrzejewska et al. (2016) J Am Soc Nephrol. 27(6), 1678-1688e). CTNS-deficient cells show and increased number of autophagosomes and reduced chaperone-mediated autophagy (Napolitano et al. (2015) EMBO Mol Med. 7(2), 158-74).

In some embodiments, the present invention provides a method of treating Fabry disease in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. In Fabry disease, deficiencies in alpha-galactosidase results in the lysosomal accumulation of globotriaosylceramide lipids. Decreased mTOR activity and increased autophagy is observed in vitro and in vivo in a cell model of Fabry in which alpha-galactosidase is knocked down with shRNA (Liebau et al. (2013) PLoS 8, e63506). Hyperactive autophagy is also observed in the brains of mice in which alpha-galactosidase is knocked out (Nelson et al. (2014) Acta Neuropathologica Communications 2, 20).

In some embodiments, the present invention provides a method of treating Mucolipidosis type IV (MLIV) in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. In MLIV, mutations of theTRPML1 lysosomal Ca(2+) channel cause disordered lysosomal membrane trafficking. An MLIV knockout in Drosophila resulted in upregulation of autophagy and a decrease in mTOR activity, both of which could be reversed by activating mTORC1 genetically or by feeding animals a high protein diet (Wong et al. (2012) Curr Biol. 22(17), 1616-1621). Increased autophagy is also observed in fibroblasts from MLIV patients (Vergarajauregui et al. (2008) Human Molecular Genetics 17, 2723-2737).

In some embodiments, the present invention provides a method of treating mental retardation in a patient in need thereof, comprising the step of administering to said patient a provided compound or pharmaceutically acceptable composition thereof. In Homo sapiens, Cereblon mutations are linked to a mild form of autosomal recessive non-syndromic mental retardation. In a mouse cereblon knockout model of retardation, loss of cereblon activates AMPK, inhibits mTOR and reduces protein translation in the cerebellum (Lee et al. (2014) J Biol Chem. 289, 23343-52; Xu et al. (2013) J Biol Chem. 288, 29573-85).

In some embodiments, the present invention provides a method of increasing neuronal protein expression in a subject, comprising the step of administering to said subject a provided compound or pharmaceutically acceptable composition thereof. In some embodiments the increase in neuronal protein expression occurs in a post-synaptic neuron. In some embodiments, the increase in neuronal protein expression includes increased expression of brain-derived neurotrophic factor (BDNF). In some embodiments, the increase in neuronal protein expression includes increased expression of glutamate receptor 1 (GluR1). In some embodiments, the increase in neuronal protein expression includes increased expression of synapsin. In some embodiments, the increase in neuronal protein expression includes increased expression of PSD95.

In some embodiments, the present invention provides a method of increasing synaptogenesis in a subject, comprising the step of administering to said subject a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the increased synaptogenesis involves synaptic remodeling. In some embodiments, the increased synaptogenesis involves induction of dendritic spines. In some embodiments, the induction of dendritic spines causes an increased density of dendritic spines. In some embodiments, the dendritic spines are thin spines. In some embodiments, the dendritic spines are mushroom spines.

In some embodiments, the present invention provides a method of enhancing synoptic function in a subject, comprising the step of administering to said subject a provided compound or pharmaceutically acceptable composition thereof. In some embodiments, the enhanced synoptic function in a subject involves an increase in excitatory postsynaptic currents (EPSC).

Pharmaceutically acceptable compositions of this invention can be administered to humans and other animals orally, rectally, parenterally, intracisternally, intravaginally, intraperitoneally, topically (as by powders, ointments, or drops), bucally, as an oral or nasal spray, or the like, depending on the severity of the infection being treated. In certain embodiments, the compounds of the invention may be administered orally or parenterally at dosage levels of about 0.01 mg/kg to about 50 mg/kg and preferably from about 1 mg/kg to about 25 mg/kg, of subject body weight per day, one or more times a day, to obtain the desired therapeutic effect.

Liquid dosage forms for oral administration include, but are not limited to, pharmaceutically acceptable emulsions, microemulsions, solutions, suspensions, syrups and elixirs. In addition to the active compounds, the liquid dosage forms may contain inert diluents commonly used in the art such as, for example, water or other solvents, solubilizing agents and emulsifiers such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, dimethylformamide, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor, and sesame oils), glycerol, tetrahydrofurfuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof. Besides inert diluents, the oral compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming agents.

Injectable preparations, for example, sterile injectable aqueous or oleaginous suspensions may be formulated according to the known art using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution, suspension or emulsion in a nontoxic parenterally acceptable diluent or solvent, for example, as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution, U.S.P. and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil can be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid are used in the preparation of injectables.

Injectable formulations can be sterilized, for example, by filtration through a bacterial-retaining filter, or by incorporating sterilizing agents in the form of sterile solid compositions which can be dissolved or dispersed in sterile water or other sterile injectable medium prior to use.

In order to prolong the effect of a compound of the present invention, it is often desirable to slow the absorption of the compound from subcutaneous or intramuscular injection. This may be accomplished by the use of a liquid suspension of crystalline or amorphous material with poor water solubility. The rate of absorption of the compound then depends upon its rate of dissolution that, in turn, may depend upon crystal size and crystalline form. Alternatively, delayed absorption of a parenterally administered compound form is accomplished by dissolving or suspending the compound in an oil vehicle. Injectable depot forms are made by forming microencapsule matrices of the compound in biodegradable polymers such as polylactide-polyglycolide. Depending upon the ratio of compound to polymer and the nature of the particular polymer employed, the rate of compound release can be controlled. Examples of other biodegradable polymers include poly(orthoesters) and poly(anhydrides). Depot injectable formulations are also prepared by entrapping the compound in liposomes or microemulsions that are compatible with body tissues.

Compositions for rectal or vaginal administration are preferably suppositories which can be prepared by mixing the compounds of this invention with suitable non-irritating excipients or carriers such as cocoa butter, polyethylene glycol or a suppository wax which are solid at ambient temperature but liquid at body temperature and therefore melt in the rectum or vaginal cavity and release the active compound.

Solid dosage forms for oral administration include capsules, tablets, pills, powders, and granules. In such solid dosage forms, the active compound is mixed with at least one inert, pharmaceutically acceptable excipient or carrier such as sodium citrate or dicalcium phosphate and/or a) fillers or extenders such as starches, lactose, sucrose, glucose, mannitol, and silicic acid, b) binders such as, for example, carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidinone, sucrose, and acacia, c) humectants such as glycerol, d) disintegrating agents such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and sodium carbonate, e) solution retarding agents such as paraffin, f) absorption accelerators such as quaternary ammonium compounds, g) wetting agents such as, for example, cetyl alcohol and glycerol monostearate, h) absorbents such as kaolin and bentonite clay, and i) lubricants such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof. In the case of capsules, tablets and pills, the dosage form may also comprise buffering agents.

Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polyethylene glycols and the like. The solid dosage forms of tablets, dragees, capsules, pills, and granules can be prepared with coatings and shells such as enteric coatings and other coatings well known in the pharmaceutical formulating art. They may optionally contain opacifying agents and can also be of a composition that they release the active ingredient(s) only, or preferentially, in a certain part of the intestinal tract, optionally, in a delayed manner. Examples of embedding compositions that can be used include polymeric substances and waxes. Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polyethylene glycols and the like.

The active compounds can also be in micro-encapsulated form with one or more excipients as noted above. The solid dosage forms of tablets, dragees, capsules, pills, and granules can be prepared with coatings and shells such as enteric coatings, release controlling coatings and other coatings well known in the pharmaceutical formulating art. In such solid dosage forms the active compound may be admixed with at least one inert diluent such as sucrose, lactose or starch. Such dosage forms may also comprise, as is normal practice, additional substances other than inert diluents, e.g., tableting lubricants and other tableting aids such a magnesium stearate and microcrystalline cellulose. In the case of capsules, tablets and pills, the dosage forms may also comprise buffering agents. They may optionally contain opacifying agents and can also be of a composition that they release the active ingredient(s) only, or preferentially, in a certain part of the intestinal tract, optionally, in a delayed manner. Examples of embedding compositions that can be used include polymeric substances and waxes.

Dosage forms for topical or transdermal administration of a compound of this invention include ointments, pastes, creams, lotions, gels, powders, solutions, sprays, inhalants or patches. The active component is admixed under sterile conditions with a pharmaceutically acceptable carrier and any needed preservatives or buffers as may be required. Ophthalmic formulation, ear drops, and eye drops are also contemplated as being within the scope of this invention. Additionally, the present invention contemplates the use of transdermal patches, which have the added advantage of providing controlled delivery of a compound to the body. Such dosage forms can be made by dissolving or dispensing the compound in the proper medium. Absorption enhancers can also be used to increase the flux of the compound across the skin. The rate can be controlled by either providing a rate controlling membrane or by dispersing the compound in a polymer matrix or gel.

According to one embodiment, the invention relates to a method of modulating Sestrin-GATOR2 interaction thereby selectively modulating mTORC1 activity indirectly in a biological sample comprising the step of contacting said biological sample with a compound of this invention, or a composition comprising said compound.

The term “biological sample”, as used herein, includes, without limitation, cell cultures or extracts thereof; biopsied material obtained from a mammal or extracts thereof; and blood, saliva, urine, feces, semen, tears, or other body fluids or extracts thereof.

Another embodiment of the present invention relates to a method of modulating Sestrin-GATOR2 interaction thereby selectively modulating mTORC1 activity indirectly in a patient comprising the step of administering to said patient a compound of the present invention, or a composition comprising said compound.

According to another embodiment, the invention relates to a method of modulating Sestrin-GATOR2 interaction thereby selectively modulating mTORC1 activity indirectly in a patient comprising the step of administering to said patient a compound of the present invention, or a composition comprising said compound. In other embodiments, the present invention provides a method for treating a disorder mediated by mTORC1 in a patient in need thereof, comprising the step of administering to said patient a compound according to the present invention or pharmaceutically acceptable composition thereof. Such disorders are described in detail herein.

Depending upon the particular condition, or disease, to be treated, additional therapeutic agents that are normally administered to treat that condition, may also be present in the compositions of this invention. As used herein, additional therapeutic agents that are normally administered to treat a particular disease, or condition, are known as “appropriate for the disease, or condition, being treated.”

In some embodiments, a provided compound is administered in combination with an antidepressant therapeutic agent. Antidepressent therapeutic agents are well known to one of ordinary skill in the art and include Selective Serotonin Reuptake Inhibitors (“SSRI”, e.g. sertraline, escitalopram, citalopram, fluvoxamine, fluoxetine, paroxetine), antidepressant (e.g., bupropion, venlafaxine, mirtazapine, duloxetine, amitriptyline, imipramine, selegiline, nortriptyline, trazodone, desvenlafaxine, and aripiprazole).

In some embodiments, a provided compound is administered in combination with an additional therapeutic agent or process useful for treating one or more LSDs. In some embodiments, a provided compound is administered in combination with enzyme replacement therapy, chemical chaperone therapy, bone marrow transplantation, substrate reduction therapy, a-L-iduronidase, Recombinant human N-acetylgalactosamine-4-sulphatase (arylsulphatase B), an inhibitor of glycosphingolipid biosynthesis, N-butyldeoxynojirimycin (Miglustat), a hydrophobic iminosugar, or an inhibitor of a-galactosidase A (e.g., 1-deoxy-galactonojirimycin).

Those additional agents may be administered separately from an inventive compound-containing composition, as part of a multiple dosage regimen. Alternatively, those agents may be part of a single dosage form, mixed together with a compound of this invention in a single composition. If administered as part of a multiple dosage regime, the two active agents may be submitted simultaneously, sequentially or within a period of time from one another normally within five hours from one another.

As used herein, the term “combination,” “combined,” and related terms refers to the simultaneous or sequential administration of therapeutic agents in accordance with this invention. For example, a compound of the present invention may be administered with another therapeutic agent simultaneously or sequentially in separate unit dosage forms or together in a single unit dosage form. Accordingly, the present invention provides a single unit dosage form comprising a compound of the current invention, an additional therapeutic agent, and a pharmaceutically acceptable carrier, adjuvant, or vehicle.

The amount of both an inventive compound and additional therapeutic agent (in those compositions which comprise an additional therapeutic agent as described above) that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. Preferably, compositions of this invention should be formulated so that a dosage of between 0.01-100 mg/kg body weight/day of an inventive compound can be administered.

In those compositions which comprise an additional therapeutic agent, that additional therapeutic agent and the compound of this invention may act synergistically. Therefore, the amount of additional therapeutic agent in such compositions will be less than that required in a monotherapy utilizing only that therapeutic agent. In such compositions a dosage of between 0.01-1,000 μg/kg body weight/day of the additional therapeutic agent can be administered.

The amount of additional therapeutic agent present in the compositions of this invention will be no more than the amount that would normally be administered in a composition comprising that therapeutic agent as the only active agent. Preferably the amount of additional therapeutic agent in the presently disclosed compositions will range from about 50% to 100% of the amount normally present in a composition comprising that agent as the only therapeutically active agent.

The compounds of this invention, or pharmaceutical compositions thereof, may also be incorporated into compositions for coating an implantable medical device, such as prostheses, artificial valves, vascular grafts, stents and catheters. Vascular stents, for example, have been used to overcome restenosis (re-narrowing of the vessel wall after injury). However, patients using stents or other implantable devices risk clot formation or platelet activation. These unwanted effects may be prevented or mitigated by pre-coating the device with a pharmaceutically acceptable composition comprising a kinase inhibitor. Implantable devices coated with a compound of this invention are another embodiment of the present invention.

EXEMPLIFICATION

As depicted in the Examples below, in certain exemplary embodiments, compounds are prepared according to the following general procedures. It will be appreciated that, although the general methods depict the synthesis of certain compounds of the present invention, the following general methods, and other methods known to one of ordinary skill in the art, can be applied to all compounds and subclasses and species of each of these compounds, as described herein.

List of Abbrevations Used in the Experimental Section.

-   -   4 A MS: 4 Å molecular sieves     -   AcOH: acetic acid     -   ACN: acetonitrile     -   Anhyd: anhydrous     -   Aq: aqueous     -   Bn: benzyl     -   Boc: tert-butoxycarbonyl     -   CbzCl: benzyl chloroformate     -   Cbz-OSU: N-(Benzyloxycarbonyloxy)succinimide     -   Cu(OAc)₂: copper(II) acetate     -   d: days     -   DAST: diethylaminosulfur trifluoride     -   DBU: 1,8-diazobicyclo[5.4.0]undec-7-ene     -   DCE: 1,2-dichloroethane     -   DCM: dichloromethane     -   DEA: diethylamine     -   DIBAL-H: diisobutylaluminium hydride     -   DIPEA: N,N-diisopropylethylamine     -   DMA: N,N-dimethylacetamide     -   DMAP: 4-dimethylaminopyridine     -   DMF: N,N-dimethylformamide     -   DMSO-dimethyl sulfoxide     -   DPPA: diphenylphosphoryl azide     -   EDC: l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride     -   ee: enantiomeric excess     -   ESI: electrospray ionization     -   Et₃N: triethylamine     -   Et₂O: diethyl ether     -   EtOAc: ethyl acetate     -   EtOH: ethanol     -   Fmoc: fluorenylmethyloxycarbonyl     -   Fmoc-OSu: N-(9-fluorenylmethoxycarbonyloxy)succinimide     -   h: hours     -   HATU:         1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium         3-oxid     -   hexafluorophosphate     -   HCOONH₄: ammonium formate     -   HPLC: high performance liquid chromatography     -   IBX: 2-Iodoxybenzoic acid     -   IPA: isopropyl alcohol     -   KOAc: potassium acetate     -   M: molar     -   Me: methyl     -   MeOH: methanol     -   mins: minutes     -   mL: milliliters     -   mM: millimolar     -   mmol: millimoles     -   MTBE: methyl tert-butyl ether     -   NaBH₃CN: sodium cyanoborohydride     -   Na₂CO₃: sodium carbonate     -   NaHCO₃: sodium bicarbonate     -   NMP: N-methylpyrrolidine     -   NMR: Nuclear Magnetic Resonance     -   ° C.: degrees Celsius     -   PBS: phosphate buffered saline     -   Pd/C: Palladium on carbon     -   Pd(OH)₂/C: Pearlman's catalyst     -   PE: petroleum ether     -   PhNH₂: aniline     -   PPh₃: triphenylphosphine     -   Rel: relative     -   rt: room temperature     -   sat: saturated     -   SFC: supercritical fluid chromatography     -   SOCl₂: thionyl chloride     -   TBAB: Tetra-n-butylammonium bromide     -   tBuOK: potassium tert-butoxide     -   TEA: triethylamine     -   Tf: trifluoromethanesulfonate     -   TfAA: trifluoromethanesulfonic anhydride     -   TFA: trifluoracetic acid     -   TIPS: triisopropylsilyl     -   THF: tetrahydrofuran     -   TMSCN: trimethyl silyl cyanide     -   pTSA: para-toluenesulfonic acid     -   TsOH: p-Toluenesulfonic acid

Preparation of representative non-limiting examples of provided compounds are described below.

Example 1: (S)-2-(dimethylamino)-4-methylpentanoic Acid [I-1]

Procedures and Characterization: Step 1: (S)-2-(dimethylamino)-4-methylpentanoic Acid

Formaldehyde (38%, 24.0 g) and Pd/C (10%, 500 mg) were added to a solution of (S)-2-amino-4-methyl pentanoic acid (2.0 g, 15.24 mmol) in resulting solution was filtered (60 mL). The mixture was hydrogenated at room temperature for two days and filtered to remove the catalyst. The filtrate was concentrated to dryness and EtOH (30 mL) was added to the residue. The mixture was stirred for 1 h and filtered. The filtrate was concentrated to afford (S)-2-(dimethylamino)-4-methylpentanoic acid (1.3 g, 8.16 mmol, 53%) as a white powder. ESI-MS (EI⁺, m/z): 160.2 [M+H]⁺. ¹H-NMR (400 MHz, MeOD-d₄): δ 3.47 (dd, 0.7=4.4 Hz, 10.0 Hz, 1H), 2.85 (S, 6H), 1.89-1.74 (m, 2H), 1.62-1.55 (m, 1H), 1.00 (dd, J=2.8 Hz, 6.8 Hz, 6H).

Examples 2 and 3: (S)-2-amino-7,7,7-trifluoroheptanoic Acid Hydrochloride [I-2] and (R)-2-amino-7,7,7-trifluoroheptanoic Acid Hydrochloride [I-3]

Procedures and Characterization: Step 1: 1,1,1-Trifluoro-5-iodopentane

To a solution of 5,5,5-trifluoropentan-1-ol (2.0 g, 14.0 mmol), imidazole (1.48 g, 21.7 mmol) and PPh₃ (5.5 g, 21.0 mmol) in DCM (40 mL) was added I₂ (4.45 g, 17.5 mmol) with ice-bath. The mixture was warmed to room temperature and stirred overnight. To the mixture of above was added Et₂O (50 mL), and then stirred for 10 mins. The mixture was filtered, and the filtrate was evaporated at 65° C. to remove the solvent under atmospheric pressure, the residue was diluted with Et₂O (30 mL), the mixture was filtered, and the filtrate was used for the next step.

Step 2: (S)-tert-butyl 2-(diphenylmethyleneamino)-7,7,7-trifluoroheptanoate and (R)-tert-Butyl 2-(diphenylmethyleneamino)-7,7,7-trifluoroheptanoate

To a solution of tert-butyl 2-(diphenylmethyleneamino)acetate (2.0 g, 6.78 mmol) and TBAB (109 mg, 0.339 mmol) in toluene (35 mL) and DCM (15 mL) was added KOH (50%, 20 mL) at −10° C., after 5 mins, the above solution of 1,1,1-trifluoro-5-iodopentane in Et₂O (30 mL) was added dropwise over 5 mins, the result mixture was stirred at −10° C. to 0° C. for 1 h. The solution was diluted with water (200 mL) and extracted with EA (100 mL). The organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum, the crude product was purified by chromatography (silica, ethyl acetate/petroleum ether=1/10) and then chiral-prep-HPLC [column, R, R-whelk-ol 4.6*250 mm 5 um; solvent, MeOH (0.2% Methanol Ammonia)] to afford (S)-tert-butyl 2-(diphenylmethyleneamino)-7,7,7-trifluoroheptanoate (200 mg, 0.48 mmol, 7.1%) and (R)-tert-butyl 2-(diphenylmethyleneamino)-7,7,7-trifluoroheptanoate (200 mg, 0.48 mmol, 7.1%).

(S)-tert-butyl 2-(diphenylmethyleneamino)-7,7,7-trifluoroheptanoate (200 mg, 0.48 mmol, 7.1%). ESI-MS (EI+, m/z): 243.1 [M+H]+. ¹H NMR (500 MHz, CDCl₃): δ 8.64 (d, J=8.0 Hz, 2H), 7.43-7.46 (m, 3H), 7.38-7.39 (m, 1H), 7.31-7.34 (m, 2H), 7.15-7.17 (m, 2H), 3.91 (dd, J=5.5 Hz, 7.5 Hz, 1H), 2.00-2.05 (m, 2H), 1.88-1.92 (m, 2H), 1.31-1.52 (m, 13H).

(R)-tert-butyl 2-(diphenylmethyleneamino)-7,7,7-trifluoroheptanoate (200 mg, 0.48 mmol, 7.1%). ESI-MS (EI+, m/z): 243.1 [M+H]+. ¹H NMR (500 MHz, CDCl₃): δ 8.64 (d, J=7.0 Hz, 2H), 7.43-7.46 (m, 3H), 7.38-7.39 (m, 1H), 7.31-7.34 (m, 2H), 7.15-7.17 (m, 2H), 3.92 (dd, j=5.5 Hz, 7.5 Hz, 1H), 2.00-2.05 (m, 2H), 1.88-1.92 (m, 2H), 1.31-1.52 (m, 13H).

Step 3: (S)-2-amino-7,7,7-trifluoroheptanoic Acid Hydrochloride [I-2]

A solution of (S)-tert-butyl 2-(diphenylmethyleneamino)-7,7,7-trifluoroheptanoate (200 mg, 0.48 mmol) in 6 M HCl (10 mL) and dioxane (5 mL) was heated to 100° C. for 17 hrs. The solution was extracted with Et₂O (10 mL×2), the aqueous phase was concentrated to dryness to afford (S)-2-amino-7,7,7-trifluoroheptanoic acid hydrochloride (I-2) as a white solid (82.7 mg, 0.35 mmol, 74%). ESI-MS (EI+, m/z): 200.1 [M+H]+. 1H NMR (500 MHz, D₂O) δ 3.93 (t, J=6.0 Hz, 1H), 2.10-2.15 (m, 2H), 1.83-1.90 (m, 2H), 1.40-1.56 (m, 4H).

Step 4: (R)-2-amino-7,7,7-trifluoroheptanoic Acid Hydrochloride [I-3]

A solution of (R)-tert-butyl 2-(diphenylmethyleneamino)-7,7,7-trifluoroheptanoate (200 mg, 0.48 mmol) in 6 M HCl (10 mL) and dioxane (5 mL) was heated to 100° C. for 17 hrs. The solution was extracted with Et₂O (10 mL×2), the aqueous phase was concentrated to dryness to afford (R)-2-amino-7,7,7-trifluoroheptanoic acid hydrochloride (1-3) as a white solid (91.6 mg, 0.39 mmol, 82%). ESI-MS (EI+, m/z): 200.1 [M+H]+. 1H NMR (500 MHz, D₂O) δ 3.92 (t, J=6.0 Hz, 1H), 2.09-2.14 (m, 2H), 1.82-1.89 (m, 2H), 1.39-1.55 (m, 4H).

Examples 4 and 5: (S)-2-amino-4,4,4-trifluorobutanoic Acid [I-4] and (R)-2-amino-4,4,4-trifluoro Butanoic Acid [I-5]

Procedures and Characterization: Step 1: (S)-2-(benzyloxycarbonylamino)-4,4,4-trifluorobutanoic acid and (R)-2-(benzyloxycarbonylamino)-4,4,4-trifluorobutanoic Acid

N-(Benzyloxycarbonyloxy)succinimide (1.75 g, 7.01 mmol) was slowly added to a solution of 2-amino-4,4,4-trifluorobutanoic acid (1.0 g, 6.36 mmol) and NaHCO₃ (589 mg, 7.01 mmol) in acetone (60 mL) and resulting solution was filtered (60 mL) at 0° C. The mixture was stirred at rt for 16 hrs. The reaction mixture was extracted with CH₂Cl₂ (2×100 mL) and the aqueous layer was acidified with HCl (3 M) to about pH 4 and then extracted with EtOAc (3×150 mL). The organic phase was dried over Na₂SO₄ and the solvent was evaporated under vacuum. The resulting crude product was purified by chiral-prep-HPLC (column, AY-H 4.6*250 mm 5 um; solvent, EtOH) to afford (S)-2-(benzyloxycarbonylamino)-4,4,4-trifluoro butanoic acid (700 mg, 2.40 mmol, 37.8%) and (R)-2-(benzyloxy carbonylamino)-4,4,4-trifluorobutanoic acid(700 mg, 2.40 mmol, 37.8%) as white solid. ESI-MS (EI+, m/z): 314.0[M+Na]+.

(S)-2-(benzyloxycarbonylamino)-4,4,4-trifluorobutanoic acid. ¹H NMR (500 MHz, DMSO-d6): δ 13.20 (s, 1H), 7.84 (d, J=9.0 Hz, 1H), 7.40-7.30 (m, 5H), 5.06 (s, 2H), 4.31-4.27 (m, 1H), 2.85-2.58 (m, 2H).

(R)-2-(benzyloxycarbonylamino)-4,4,4-trifluorobutanoic acid. ¹H NMR (500 MHz, DMSO-d6): δ 13.21 (s, 1H), 7.85 (d, J=8.5 Hz, 1H), 7.38-7.30 (m, 5H), 5.06 (s, 2H), 4.31-4.27 (m, 1H), 2.83-2.59 (m, 2H).

Step 2: (S)-2-amino-4,4,4-trifluorobutanoic Acid [I-4]

A mixture of (S)-2-(benzyloxycarbonylamino)-4,4,4-trifluorobutanoic acid (700 mg, 2.40 mmol) and Pd/C (10%) (200 mg) in MeOH (50 mL) was stirred at rt for 2 h under hydrogen atmosphere. The mixture was filtered, and the filter cake was washed with MeOH (20 mL). The filtrate was concentrated to afford (S)-2-amino-4,4,4-trifluorobutanoic acid (1-4), (250 mg, 1.59 mmol, 66.3%) as a white solid. ESI-MS (EI+, m/z): 158.1 [M+H]+. 1H-NMR (500 MHz, DMSO-d6+1 drop TFA+1 drop D2O): δ 4.32 (t, J=6.0 Hz, 1H), 3.03-2.82 (m, 2H).

Step 3: (R)-2-amino-4,4,4-trifluorobutanoic Acid [I-5]

A mixture of (R)-2-(benzyloxycarbonylamino)-4,4,4-trifluorobutanoic acid (700 mg, 2.40 mmol) and Pd/C (10%) (200 mg) in MeOH (50 mL) was stirred at rt for 2 h under hydrogen atmosphere. The mixture was filtered, and the filter cake was washed with MeOH (20 mL). The filtrate was concentrated to afford (7/)-2-amino-4,4,4-trifluorobutanoic acid (1-5), (250 mg, 1.59 mmol, 66.3%) as a white solid. ESI-MS (EI⁺, m/z): 158.1 [M+H]⁺. ¹H-NMR (500 MHz, DMSO-d₆+1 drop TFA+1 drop D₂O): δ 4.31 (t, J=6.0 Hz, 1H), 3.03-2.83 (m, 2H).

Examples 6 and 7: (S)-2-amino-5,5,5-trifluoropentanoic Acid [I-6] and (R)-2-amino-5,5,5-trifluoropentanoic Acid [I-7]

Procedures and Characterization: Step 1: 4,4,4-Trifluorobutanal

To a solution of 4,4,4-trifluorobutan-1-ol (4.0 g, 31.3 mmol) in DMSO (80 mL) was added IBX (13.0 g, 46.9 mmol) under ice-bath. The mixture was warmed to room temperature and stirred overnight. The reaction mixture was poured into water (200 mL) and extracted with Et2O (100 mL×2), the organic phase was washed with water (100 mL×3), and brine (100 mL), dried (Na2SO4), and the solution was used for the next step.

Step 2: 2-(Benzylamino)-5,5,5-trifluoropentanenitrile

To a solution of above 4,4,4-trifluorobutanal in Et2O (200 mL) was added benzylamine (4 mL), AcOH (3.0 mL) and then TMSCN (3.5 mL) with ice-bath. The mixture was warmed to room temperature and stirred overnight. The solution was diluted with water (200 mL) and extracted with EtOAc (100 mL), the organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na2SO4), filtered and concentrated in vacuum to afford 2-(benzylamino)-5,5,5-trifluoropentanenitrile (6.7 g, crude) as a brown solid which was used for the next step. ESI-MS (EI+, m/z): 243.1 [M+H]+.

Step 3: 2-(Benzylamino)-5,5,5-trifluoropentanoic Acid

A solution of 2-(benzylamino)-5,5,5-trifluoropentanenitrile (6.7 g, crude) in cone. HCl (80 mL) and AcOH (30 mL) was heated to 95° C. for 17 hrs. The solution was concentrated to dryness, diluted with resulting solution was filtered (100 mL) and ACN (50 mL), the pH was adjusted to 3-4 with sat. NaHCO₃ solution, the mixture was filtered and dried to afford 2-(benzylamino)-5,5,5-trifluoropentanoic acid (3.5 g, 13.4 mmol, 43% for 3 steps) as a white solid. ESI-MS (EI⁺, m/z): 262.1 [M+H]⁺.

Step 4: 2-Amino-5,5,5-trifluoropentanoic Acid

A mixture of 2-(benzylamino)-5,5,5-trifluoropentanoic acid (3.3 g, 12.6 mmol) and Pd(OH)2/C (20%, 400 mg) in AcOH (60 mL) was stirred at 30° C. for 17 hrs. The mixture was filtered, and the filtrate was concentrated to dryness to afford 2-amino-5,5,5-trifluoropentanoic acid (3.0 g, crude) as a brown solid. ESI-MS (EI+, m/z): 172.2 [M+H]+.

Step 5: (S)-2-(Benzyloxycarbonylamino)-5,5,5-trifluoropentanoic acid and (R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoropentanoic Acid

To a solution of 2-amino-5,5,5-trifluoropentanoic acid (3.0 g, crude) in sat. NaHCO3 solution (100 mL) and acetone (100 mL) was added Cbz-OSu (3.45 g, 13.9 mmol) with ice-bath, after 2 h, The mixture was adjusted to pH 3 with 6 M HCl, extracted with EtOAc (50 mL×2), the organic phase was washed with water (50 mL) and brine (100 mL), dried (Na₂SO₄), and concentrated in vacuum, The crude product was purified by chromatography (silica, ethyl acetate/petroleum ether=1/2) and then chiral-prep-HPLC [column, AY-H 4.6*250 mm 5 um; solvent, MeOH (0.5% NH₄OH)] to afford (S)-2-(benzyloxycarbonylamino)-5,5,5-trifluoropentanoic acid (1.50 g, 4.92 mmol, 28%, 2 steps) and (R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoropentanoic acid (1.50 g, 4.92 mmol, 28%, for 2 steps) as white solids.

(S)-2-(benzyloxycarbonylamino)-5,5,5-trifluoropentanoic acid (1.50 g, 4.92 mmol, 28% for 2 steps). ESI-MS (EI+, m/z): 328.0 [M+Na]+. 1H-NMR (500 MHz, DMSO-d6): δ 12.86 (s, 1H), 7.71 (d, J=8.0 Hz, 1H), 7.31-7.39 (m, 5H), 5.05 (s, 2H), 4.05-4.10 (m, 1H), 2.34-2.41 (m, 1H), 2.21-2.29 (m, 1H), 1.84-1.97 (m, 2H).

(R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoropentanoic acid (1.50 g, 4.92 mmol, 28%, 2 steps) ESI-MS (EI+, m/z): 328.0 [M+Na]+. 1H-NMR (500 MHz, DMSO-d6): δ 12.85 (s, 1H), 7.71 (d, J=8.0 Hz, 1H), 7.30-7.39 (m, 5H), 5.05 (s, 2H), 4.05-4.10 (m, 1H), 2.34-2.41 (m, 1H), 2.21-2.29 (m, 1H), 1.84-1.97 (m, 2H).

Step 6: (S)-2-Amino-5,5,5-trifluoropentanoic Acid [I-6]

A mixture of (S)-2-(benzyloxycarbonylamino)-5,5,5-trifluoropentanoic acid (500 mg, 1.64 mmol) and Pd/C (10%) (50 mg) in MeOH (20 mL) was stirred at rt for 2 h under hydrogen. The mixture was filtered, and the filter cake was washed with MeOH (20 mL). The filtrate was concentrated to afford (S)-2-amino-5,5,5-trifluoropentanoic acid (1-6), (200 mg, 1.17 mmol, 71%) as a white solid. ESI-MS (EI⁺, m/z): 172.1 [M+H]⁺. ¹H-NMR (400 MHz, DMSO-d₆): δ 8.38 (s, 3H), 4.05 (d, J=4.4 Hz, 1H), 2.34-2.55 (m, 2H), 1.95-20.9 (m, 2H).

Step 7: (R)-2-Amino-5,5,5-trifluoropentanoic Acid [I-7]

A mixture of (R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoropentanoic acid (500 mg, 1.64 mmol) and Pd/C (10%) (50 mg) in MeOH (20 mL) was stirred at rt for 2h under hydrogen. The mixture was filtered, and the filter cake was washed with MeOH (20 mL). The filtrate was concentrated to afford (R)-2-amino-5,5,5-trifluoropentanoic acid (1-7), (160 mg, 0.94 mmol, 57%) as a white solid. ESI-MS (EI+, m/z): 172.1 [M+H]+. 1H-NMR (400 MHz, DMSO-d6): δ 8.38 (s, 3H), 4.05 (d, J=4.4 Hz, 1H), 2.34-2.55 (m, 2H), 1.95-20.9 (m, 2H).

Examples 8 and 9: (S)-2-amino-6,6,6-trifluorohexanoic Acid [I-8] and (R)-2-amino-6,6,6-trifluorohexanoic Acid [I-9]

Procedure and Characterization: Step 1: (S)-2-(benzyloxycarbonylamino)-6,6,6-trifluorohexanoic Acid and (R)-2-(benzyloxycarbonylamino)-6,6,6-trifluorohexanoic Acid

Benzyl carbonochloridate (554 mg, 3.25 mmol) was slowly added to a solution of 2-amino-6,6,6-trifluorohexanoic acid (556 mg, 2.5 mmol) and 1 M NaOH (25 mL, 25 mmol) in THF (25 mL) at 0° C., the mixture was stirred at rt for 16 h. The reaction mixture was extracted with DCM (2×100 mL) and the aqueous layer was acidified with HCl (3 M) to about pH 4 and then extracted with EtOAc (3×50 mL). The organic phase was dried over Na2SO4 and the solvent was evaporated under vacuum. The resulting crude product was purified by chiral-prep-HPLC (Column: AY-H (250*4.6 mm 5 um); mobile phase: n-Hexane (0.1% DEA): EtOH (0.1% DEA)=90:10) to afford (S)-2-(benzyloxycarbonylamino)-6,6,6-trifluorohexanoic acid (232 mg, 0.73 mmol, 29%) and (R)-2-(benzyloxycarbonyl amino)-6,6,6-trifluorohexanoic acid (250 mg, 0.78 mmol, 31.3%) as white solids. ESI-MS (EI+, m/z): 342.0 [M+Na]+.

(S)-2-(benzyloxycarbonylamino)-6,6,6-trifluorohexanoic acid, 1H-NMR (500 MHz, DMSO-d6): δ 12.68 (s, 1H), 7.66 (d, J=7.5 Hz, 1H), 7.38-7.32 (m, 5H), 5.04 (s, 2H), 4.00-3.96 (m, 1H), 2.28-2.19 (m, 2H), 1.80-1.51 (m, 4H).

(R)-2-(benzyloxycarbonylamino)-6,6,6-trifluorohexanoic acid, 1H-NMR (500 MHz, DMSO-d6): δ 12.68 (s, 1H), 7.67 (d, J=8.5 Hz, 1H), 7.38-7.30 (m, 5H), 5.04 (s, 2H), 4.00-3.96 (m, 1H), 2.33-2.15 (m, 2H), 1.82-1.51 (m, 4H).

Step 2: (S)-2-amino-6,6,6-trifluorohexanoic Acid [I-8]

A mixture of (S)-2-(benzyloxycarbonylamino)-6,6,6-trifluorohexanoic acid (200 mg, 0.63 mmol) and Pd/C (10%) (50 mg) in MeOH (20 mL) was stirred at rt for 2 h under hydrogen atmosphere. The mixture was filtered, and the filter cake was washed with MeOH (20 mL). The filtrate was concentrated to afford (S)-2-amino-6,6,6-trifiuorohexanoic acid (1-8), (56.2 mg, 0.30 mmol, 48.2%) as a white solid. ESI-MS (EI⁺, m/z): 186.1 [M+H]⁺. ¹H-NMR (500 MHz, DMSO-d₆+1 drop TFA+1 drop D₂O): δ 3.99 (t, J=5.5 Hz, 1H), 2.32-2.30 (m, 2H), 1.91-1.83 (m, 2H), 1.70-1.57 (m, 2H).

Step 3: (R)-2-amino-6,6,6-trifluorohexanoic Acid [I-9]

A mixture of (R)-2-(benzyloxycarbonylamino)-6,6,6-trifluorohexanoic acid (250 mg, 0.78 mmol) and Pd/C (10%) (50 mg) in MeOH (20 mL) was stirred at rt for 2 h under hydrogen atmosphere. The mixture was filtered, and the filter cake was washed with MeOH (20 mL). The filtrate was concentrated to afford (R)-2-amino-6,6,6-trifluorohexanoic acid (1-9), (48.8 mg, 0.26 mmol, 33.8%) as a white solid. ESI-MS (EI⁺, m/z): 186.1 [M+H]⁺. ¹H-NMR (500 MHz, DMSO-d₆+1 drop TFA+1 drop D₂O): δ 3.98 (t, J=6.5 Hz, 1H), 3.33-2.28 (m, 2H), 1.93-1.81 (m, 2H), 1.71-1.54 (m, 2H).

Example 11: (S)-2-(benzylamino)-4-methylpentanoic Acid [I-11]

Procedures and Characterization: Step 1: (S)-Benzyl 2-(benzylamino)-4-methylpentanoate

To a stirred solution of L-leucine benzyl ester p-toluenesulfonate (800 mg, 2.0 mmol) in MeOH (30 mL) was added benzaldehyde (0.26 g, 2.4 mmol) and potassium acetate (0.4 g, 4.1 mmol), and the mixture was stirred for 30 min at rt, then Sodium cyanoborohydride (0.2 g, 3.0 mmol) was added, the mixture was stirred for another 5 h at rt. The mixture was quenched with sat. NaHCO3 solution (50 mL), extracted with EtOAc (50 mL×2), washed with resulting solution was filtered (50 mL) and brine (50 mL). The organic phase was concentrated purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 2-(benzylamino)-4-methylpentanoate (200 mg, 0.64 mmol, 32%) as colorless oil. MS (EI+, m/z): 312.3 [M+H]+. 1H-NMR (500 MHz, MeOD): δ 7.41˜7.49 (m, 10H), 5.34 (dd, J=12.0 Hz, 45.0 Hz, 2H), 4.23 (q, J=12.0 Hz, 2H), 4.07˜4.09 (m, 3H), 1.68˜1.85 (m, 3H), 0.94 (dd, J=8.5 Hz, 20.5 Hz, 6H).

Step 2: (S)-2-(Benzylamino)-4-methylpentanoic Acid [I-11]

To a stirred solution of (S)-benzyl 2-(benzylamino)-4-methylpentanoate (50 mg, 0.16 mmol) in MeOH (5 mL) was added 1 M NaOH (0.5 mL). The reaction was stirred for 4 h at rt. The resulting solution was concentrated and the residue was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-2-(benzylamino)-4-methylpentanoic acid (1-11), (21 mg, 0.095 mmol, 58%) as white solid MS (EI+, m/z): 222.2 [M+H]+. 1H-NMR (500 MHz, DMSO-d6): δ 9.32 (s, 1H), 7.43˜7.50 (m, 5H), 4.17 (dd, J=13.0 Hz, 44.0 Hz, 2H), 3.82 (t, J=6.5 Hz, 1H), 1.68˜1.76 (m, 3H), 0.85˜0.90 (m, 6H).

Example 12: (S)-4-methyl-2-(2-phenylacetamido)pentanoic Acid [I-12]

Procedures and Characterization: Step 1: (S)-Benzyl 4-methyl-2-(2-phenylacetamido)pentanoate

To a solution of L-leucine benzyl ester p-toluenesulfonate (500 mg, 1.27 mmol), 2-phenylacetic acid (260 mg, 1.91 mmol) and HATH (726 mg, 1.91 mmol) in DMF (10 mL) was added DIPEA (410 mg, 3.18 mmol) and the solution was stirred for 2 h at rt. The solution was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 4-methyl-2-(2-phenylacetamido)pentanoate (300 mg, 0.88 mmol, 70%) as a white solid. MS (EI+, m/z): 340.2 [M+H]+.

Step 2: (S)-4-Methyl-2-(2-phenylacetamido)pentanoic Acid [I-12]

To a stirred solution of (S)-benzyl 4-methyl-2-(2-phenylacetamido)pentanoate (250 mg, 0.74 mmol) in EtOH (10 mL) was added a catalytic amount of Pd/C (10%, 20 mg). The reaction was stirred under hydrogen atmosphere for 3 h at 50° C. The resulting solution was filtered and concentrated to afford (S)-4-methyl-2-(2-phenylacetamido)pentanoic acid (1-12), (100 mg, 0.40 mmol, 54%) as a white solid. MS (EI+, m/z): 250.2 [M+H]+. 1H-NMR (500 MHz, MeOD): δ 7.24-7.32 (m, 5H), 4.44 (t, J=7.5 Hz, 1H), 3.58 (s, 2H), 1.64-1.68 (m, 3H), 0.96 (d, J=6.0 Hz, 3H), 0.91 (d, J=6.0 Hz, 3H).

Example 13: (S)-2-(isopropylamino)-4-methylpentanoic Acid [I-13]

Procedures and Characterization: Step 1: (S)-Benzyl 2-(isopropylamino)-4-methylpentanoate

To a stirred solution of L-leucine benzyl ester p-toluenesulfonate (1.0 g, 2.53 mmol) in MeOH (30 mL) was added acetone (177 mg, 3.05 mmol) and potassium acetate (0.5 g, 5.08 mmol), and the mixture was stirred for 30 min at rt, then sodium cyanoborohydride (0.24 g, 3.81 mmol) was added, the mixture was stirred for another 3 h at rt. The mixture was quenched with sat. NaHCO3 solution (50 mL), extracted with EtOAc (50 mL×2), washed with resulting solution was filtered (50 mL) and brine (50 mL). The organic phase was concentrated purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 2-(isopropylamino)-4-methylpentanoate (200 mg, 0.76 mmol, 30%) as a colorless oil. MS (EI+, m/z): 264.3 [M+H]+. 1H-NMR (500 MHz, , MeOD): δ 7.22˜7.29 (m, 5H), 5.07 (dd, J=11.5 Hz, 17.0 Hz, 2H), 3.33 (dd, J=6.5 Hz, 8.5 Hz, 1H), 2.54˜2.59 (m, 1H), 1.30˜1.48 (m, 3H), 0.72˜0.94 (m, 12H).

Step 2: (S)-2-(Isopropylamino)-4-methylpentanoic Acid [I-13]

To a stirred solution of (S)-benzyl 2-(isopropylamino)-4-methylpentanoate (200 mg, 0.76 mmol) in MeOH (10 mL), a catalytic amount of Pd/C (10%, 50 mg) were added. The reaction was stirred under hydrogen atmosphere for 24 h at rt. The result solution was filtered and the filtration was concentrated to afford (S)-2-(isopropylamino)-4-methylpentanoic acid (I-13), (100 mg, 0.57 mmol, 76%) as a white solid. MS (EI+, m/z): 174.3 [M+H]+. 1H-NMR (500 MHz, MeOD): δ 3.56 (dd, J=6.0 Hz, 8.5 Hz, 1H), 3.33-3.40 (m, 1H), 1.75-1.86 (m, 2H), 1.53-1.58 (m, 1H), 1.31-1.36 (m, 6H), 0.96-1.02 (m, 6H). 3.85 (dd, J=5.5 Hz, 8.5 Hz, 1H), 2.87 (q, J=6.0 Hz, 1H), 2.68 (dd, J=7.5 Hz, 12.0 Hz, 1H), 1.92-1.99 (m, 1H), 1.65-1.78 (m, 3H), 0.88-0.96 (m, 12H).

Example 14: (S)-2-(isobutylamino)-4-methylpentanoic Acid [I-14]

Procedures and Characterization: Step 1: (S)-Benzyl 2-(isobutylamino)-4-methylpentanoate

To a stirred solution of L-leucine benzyl ester p-toluenesulfonate (1.0 g, 2.53 mmol) in MeOH (30 mL) was added isobutyraldehyde (0.22 g, 3.05 mmol) and potassium acetate (0.5 g, 5.08 mmol), and the mixture was stirred for 30 min at rt, then sodium cyanoborohydride (0.24 g, 3.81 mmol) was added. The mixture was stirred for another 5 h at rt. The mixture was quenched with sat. NaHCO3 solution (50 mL), extracted with EtOAc (50 mL×2), washed with resulting solution was filtered (50 mL) and brine (50 mL). The organic phase was concentrated purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 2-(isobutylamino)-4-methylpentanoate (300 mg, 1.08 mmol, 50%) as a colorless oil. MS (EI+, m/z): 278.2 [M+H]+. 1H-NMR (500 MHz, DMSO-d6): δ 9.16 (s, 1H), 9.14 (d, J=17.5 Hz, 2H), 7.42-7.43 (m, 5H), 5.28 (q, J=12.0 Hz, 2H), 4.08-4.09 (m, 1H), 2.87-2.89 (m, 1H), 2.65-2.66 (m, 1H), 1.91-1.95 (m, 1H), 1.62-1.71 (m, 3H), 0.88-0.94 (m, 12H).

Step 2: (S)-2-(Isobutylamino)-4-methylpentanoic Acid [I-14]

To a stirred solution of (S)-benzyl 2-(isobutylamino)-4-methylpentanoate (300 mg, 1.08 mmol) in MeOH (10 mL), a catalytic amount of Pd/C (10%, 50 mg) were added. The reaction was stirred under hydrogen atmosphere for 24 h at rt. The resulting solution was filtered and the filtration was concentrated to afford (S)-2-(isobutylamino)-4-methylpentanoic acid (I-14), (150 mg, 0.8 mmol, 74%) as a white solid. MS (EI+, m/z): 188.3 [M+H]+. 1H-NMR (500 MHz, DMSO-d6): δ 8.82 (s, 2H), 3.85 (dd, J=5.5 Hz, 8.5 Hz, 1H), 2.87 (q, J=6.0 Hz, 1H), 2.68 (dd, J=7.5 Hz, 12.0 Hz, 1H), 1.92-1.99 (m, 1H), 1.65-1.78 (m, 3H), 0.88-0.96 (m, 12H).

Example 15: (S)-2-benzamido-4-methylpentanoic Acid [I-15]

Procedures and Characterization: Step 1: (S)-Benzyl 2-benzamido-4-methylpentanoate

To a solution of L-leucine benzyl ester p-toluenesulfonate (500 mg, 1.27 mmol), benzoic acid (223 mg, 1.91 mmol) and HATU (726 mg, 1.91 mmol) in DMF (10 mL) was added DIPEA (410 mg, 3.18 mmol) and the solution was stirred for 2 h at rt. The solution was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 2-benzamido-4-methylpentanoate (300 mg, 0.92 mmol, 73%) as a white solid. MS (EI+, m/z): 326.2 [M+H]+.

Step 2: (S)-2-Benzamido-4-methylpentanoic Acid [I-15]

To a stirred solution of (S)-benzyl 2-benzamido-4-methylpentanoate (100 mg, 0.46 mmol) in EtOH (10 mL) was added a catalytic amount of Pd/C (10%, 20 mg). The reaction was stirred under hydrogen atmosphere for 3 h at 50° C. The resulting solution was filtered and concentrated to afford (S)-2-benzamido-4-methylpentanoic acid (1-15), (100 mg, 0.42 mmol, 65%) as a white solid. MS (EI+, m/z): 236.2 [M+H]+. 1H-NMR (400 MHz, MeOD): δ 7.87 (t, J=6.5 Hz, 2H), 7.47-7.57 (m, 3H), 4.69 (dd, J=4.0 Hz, 11.0 Hz, 1H), 1.75-1.84 (m, 3H), 1.01 (dd, J=6.5 Hz, 10.5 Hz, 6H).

Example 16: (S)-2-isobutyramido-4-methylpentanoic Acid [I-16]

Procedures and Characterization: Step 1: (S)-Benzyl 2-isobutyramido-4-methylpentanoate

To a solution of L-leucine benzyl ester p-toluenesulfonate (500 mg, 1.27 mmol), isobutyric acid (168 mg, 1.91 mmol) and HATU (726 mg, 1.91 mmol) in DMF (10 mL) was added DIPEA (410 mg, 3.18 mmol) and the solution was stirred for 2 h at rt. The solution was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 2-isobutyramido-4-methylpentanoate (300 mg, 1.03 mmol, 81%) as a white solid. MS (EI+, m/z): 292.2 [M+H]+.

Step 2: (S)-2-Isobutyramido-4-methylpentanoic Acid [I-16]

To a stirred solution of (S)-benzyl 2-(cyclohexanecarboxamido)-4-methylpentanoate (200 mg, 0.69 mmol) in EtOH (10 mL) was added a catalytic amount of Pd/C (10%, 20 mg). The reaction was stirred under hydrogen atmosphere for 3 h at 50° C. The resulting solution was filtered and concentrated to afford (S)-2-isobutyramido-4-methylpentanoic acid (100 mg, 0.50 mmol, 73%) as a white solid. MS (EI+, m/z): 202.2 [M+H]+. 1H-NMR (400 MHz, MeOD): δ 4.43 (t, J=6.4 Hz, 1H), 2.49-2.56 (m, 1H), 1.60-1.74 (m, 3H), 1.12 (dd, J=2.4 Hz, 6.8 Hz, 6H), 0.96 (dd, J=6.4 Hz, 16.0 Hz, 6H).

Example 17: (S)-2-(cyclohexanesulfonamido)-4-methylpentanoic Acid [I-17]

Procedures and Characterization: Step 1: (S)-Benzyl 2-(cyclohexanesulfonamido)-4-methylpentanoate

To a solution of (S)-benzyl 2-amino-4-methylpentanoate 4-methylbenzenesulfonate (500 mg, 1.27 mmol) and Et3N (642.89 mg, 6.35 mmol) in DMF (3 mL), cooled with an ice-bath, was added cyclohexanesulfonyl chloride (278.53 mg, 1.52 mmol). The mixture was stirred at 25° C. for 2 hrs. The solution was diluted with ethyl acetate (10 mL), washed with resulting solution was filtered (10 mL×3) and brine (10 mL), dried with anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 2-(cyclohexanesulfonamido)-4-methylpentanoate (200 mg, 0.544 mmol, 98%) as a white solid. ESI-MS (EI+, m/z): 368.3 [M+H]+. 1H-NMR (500 MHz, DMSO-d6) δ 7.70 (d, J=9.0 Hz, 1H), 7.38 (t, J=6.5 Hz, 4H), 7.37-7.32 (m, 1H), 5.14 (q, J=12.5 Hz, 2H), 3.91 (td, J=5.0 Hz, 9.5 Hz, 1H), 2.69-2.74 (m, 1H), 2.05 (d, J=12.5 Hz, 1H), 1.97 (d, J=12.5 Hz, 1H), 1.74-1.67 (m, 2H), 1.57-1.51 (m, 2H), 1.50-1.44 (m, 1H), 1.36-0.99 (m, 5H), 0.87 (dt, J=10.5 Hz, J=20.5 Hz, 6H).

Step 2: (S)-2-(Cyclohexanesulfonamido)-4-methylpentanoic Acid [I-17]

To a solution of (S)-benzyl 2-(cyclohexanesulfonamido)-4-methylpentanoate (192 mg, 0.552 mmol) in EtOH (3 mL), was added Pd/C (20 mg, 10%). The reaction mixture was stirred at 50° C. for 4 h under hydrogen. The mixture was filtered, and the filter cake was washed with MeOH (10 mL). The filtrate was concentrated to afford (S)-2-(cyclohexanesulfonamido)-4-methylpentanoic acid (1-17), (23.3 mg, 0.084 mmol, 100%) as a white solid. ESI-MS (EI⁺, m/z): 300.2 [M+Na]⁺. NMR (500 MHz, DMSO-d₆) δ 12.75 (s, 1H), 7.47 (d, J=9.0 Hz, 1H), 3.76 (td, J=5.0 Hz, 9.5 Hz, 1H), 2.82-2.69 (m, 1H), 2.18-1.97 (m, 2H), 1.82-1.69 (m, 3H), 1.61 (d, j=12.5 Hz, 1H), 1.54-1.40 (m, 2H), 1.39-1.07 (m, 5H), 0.95-0.80 (m, 6H).

Example 18: (S)-4-methyl-2-(phenylmethylsulfonamido)pentanoic Acid [I-18]

Procedures and Characterization: Step 1: (S)-Benzyl 4-methyl-2-(phenylmethylsulfonamido)pentanoate

To a solution of (S)-benzyl 2-amino-4-methylpentanoate 4-methylbenzenesulfonate (500 mg, 1.27 mmol) and Et₃N (642.89 mg, 6.35 mmol) in DMF (3 mL), cooled with an ice-bath, was added phenylmethanesulfonyl chloride (290.71 mg, 1.52 mmol). The mixture was stirred at 25° C. for 2 hrs. The solution was diluted with ethyl acetate (10 mL), washed with resulting solution was filtered (10 mL×3) and brine (10 mL), dried with anhydrous sodium sulfate, filtered and concentrated in vacuum. The crude product was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 4-methyl-2-(phenylmethylsulfonamido)pentanoate (149 mg, 0.396 mmol, 90%) as a white solid. ESI-MS (EI+, m/z): 398.0 [M+Na]+. 1H-NMR (500 MHz, DMSO-d6) δ 7.81 (d, J=8.5 Hz, 1H), 7.52-7.18 (m, 9H), 5.15 (s, 2H), 4.28 (dd, J=13.5 Hz, 44.5 Hz, 2H), 3.87 (dd, J=8.0 Hz, 15.0 Hz, 1H), 1.57-1.15 (m, 4H), 0.82 (dd, J=4.5 Hz, 6.0 Hz, 6H).

Step 2: (S)-4-Methyl-2-(phenylmethylsulfonamido)pentanoic Acid [I-18]

To a solution of (S)-benzyl 4-methyl-2-(phenylmethylsulfonamido)pentanoate (121 mg, 0.322 mmol) in EtOH (3 mL), was added Pd/C (20 mg, 10%). This reaction mixture was stirred at 50° C. for 4 h under hydrogen. The mixture was filtered, and the filter cake was washed with MeOH (10 mL). The filtrate was concentrated to afford (S)-4-methyl-2-(phenylmethylsulfonamido)pentanoic acid (1-18), (41.2 mg, 0.144 mmol, 100%) as a white solid. ESI-MS (EI+, m/z): 308.0 [M+Na]+. 1H NMR (500 MHz, DMSO-d6) δ 12.77 (s, 1H), 7.59 (d, J=8.5 Hz, 1H), 7.47-7.25 (m, 5H), 4.30 (dd, J=13.5 Hz, 37.0 Hz, 2H), 3.75 (dd, J=7.5 Hz, 15.5 Hz, 1H), 1.65 (dt, J=6.5 Hz, 13.5 Hz, 1H), 1.45 (t, J=7.2 Hz, 2H), 0.85 (dd, J=1.5 Hz, 6.5 Hz, 6H).

Example 19: (S)-4-methyl-2-(methylsulfonamido)pentanoic Acid [I-19]

Procedures and Characterization: Step 1: (S)-Benzyl 4-methyl-2-(methylsulfonamido)pentanoate

To a solution of (S)-benzyl 2-amino-4-methylpentanoate 4-methylbenzenesulfonate (500 mg, 1.27 mmol) and Et₃N (642.89 mg, 6.35 mmol) in DMF (3 mL), cooled with an ice-bath, was added methanesulfonyl chloride (290.71 mg, 1.52 mmol), the mixture was stirred at 25° C. for 2 h. The solution was diluted with ethyl acetate (10 mL), washed with resulting solution was filtered (10 mL×3) and brine (10 mL), dried with anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 4-methyl-2-(methylsulfonamido)pentanoate (192 mg, 0.641 mmol, 98%) as a white solid. ESI-MS (EI⁺, m/z): 323.0 [M+Na]⁺. ¹H-NMR (500 MHz, DMSO-d₆) δ 7.79 (d, J=8.8 Hz, 1H), 7.42-7.36 (m, 4H), 7.37-7.32 (m, 1H), 5.16 (s, 2H), 3.97 (td, J=6.0 Hz, 9.0 Hz, 1H), 2.85 (s, 3H), 1.68 (dq, J=6.5 Hz, 13.0 Hz, 1H), 1.54-1.46 (m, 2H), 0.91-0.82 (m, 6H).

Step 2: (S)-4-Methyl-2-(methylsulfonamido)pentanoic Acid [I-19]

To a solution of (S)-benzyl 4-methyl-2-(methylsulfonamido)pentanoate (149 mg, 0.497 mmol) in EtOH (3 mL) was added Pd/C (20 mg, 10%). This reaction mixture was stirred at 50° C. for 4 h under hydrogen atmosphere. The mixture was filtered, and the filter cake was washed with MeOH (10 mL). The filtrate was concentrated to afford (S)-4-methyl-2-(methylsulfonamido)pentanoic acid (1-19), (31.4 mg, 0.150 mmol, 100%) as a white solid. ESI-MS (EI⁺, m/z): 232.1 [M+Na]⁺. ¹H NMR (500 MHz, DMSO-d₆) δ 12.82 (s, 1H), 7.56 (d, J=9.0 Hz, 1H), 3.82 (dd, J=8.0 Hz, 15.5 Hz, 1H), 2.88 (s, 3H), 1.72 (dt, J=6.5 Hz, 13.0 Hz, 1H), 1.48 (t, J=7.0 Hz, 2H), 0.89 (t, J=7.0 Hz, 6H).

Example 20: (S)-2-amino-4-methyl-N-phenylpentanamide [I-20]

Procedures and Characterization: Step 1: (S)-benzyl 4-methyl-1-oxo-1-(phenylamino)pentan-2-ylcarbamate

To a solution of (S)-2-(benzyloxycarbonylamino)-4-methylpentanoic acid (1.0 g, 3.77 mmol) in DMF (20 mL) was added aniline (702 mg, 7.55 mmol), HATU (1.72 g, 4.52 mmol) and Et3N (1.14 g, 11.31 mmol) at rt. After 2 hrs, the solution was diluted with EtOAc (80 mL), washed with resulting solution was filtered (80 mL×3) and brine (80 mL), dried (Na2SO4), filtered and concentrated in vacuo. The crude product was purified by chromatography (silica, ethyl acetate/petroleum ether=1/3) to afford (S)-benzyl 4-methyl-1-oxo-1-(phenylamino)pentan-2-ylcarbamate (350 mg, 1.03 mmol, 27%) as a white solid. ESI-MS (EI+, m/z): 341.1 [M+H]+.

Step 2: (S)-2-amino-4-methyl-N-phenylpentanamide [I-20]

A mixture of (S)-benzyl 4-methyl-1-oxo-1-(phenylamino)pentan-2-ylcarbamate (350 mg, 1.03 mmol) and Pd/C (10%, 50 mg) in MeOH (10 mL) was stirred at rt for 2 h under hydrogen. The mixture was filtered, and the filter cake was washed with MeOH (10 mL). The filtrate was concentrated to afford (S)-2-amino-4-methyl-N-phenylpentanamide (1-20), (100 mg, 0.49 mmol, 47%) as a white solid. ESI-MS (EI+, m/z): 207.2 [M+H]+. 1H-NMR (500 MHz, DMSO-d6): δ 9.86 (s, 1H), 7.63 (dd, J=1.0 Hz, 8.5 Hz, 2H), 7.31-7.27 (m, 2H), 7.03 (t, J=7.5 Hz, 1H), 3.31 (dd, J=5.0 Hz, 8.5 Hz, 1H), 1.80-1.71 (m, 1H), 1.50-1.44 (m, 1H), 1.35-1.29 (m, 1H), 0.90 (dd, j=6.5 Hz, 14.0 Hz, 6H).

Example 21: (S)-2-amino-N,4-dimethylpentanamide [I-21]

Procedures and Characterization: Step 1: (S)-Benzyl 4-methyl-1-(methylamino)-1-oxopentan-2-ylcarbamate

To a solution of (S)-2-(benzyloxycarbonylamino)-4-methylpentanoic acid (1.0 g, 3.77 mmol) in DMF (20 mL) was added MeNH2□HCl (509 mg, 7.54 mmol), HATU (1.72 g, 4.52 mmol) and Et3N (1.14 g, 11.31 mmol) at 25° C. After 2h, the solution was diluted with EtOAc (80 mL), washed with resulting solution was filtered (80 mL×3) and brine (80 mL), dried (Na2SO4), filtered and concentrated in vacuo. The crude product was purified by chromatography (silica, ethyl acetate/petroleum ether=1/3) to afford (S)-benzyl 4-methyl-1-(methylamino)-1-oxopentan-2-ylcarbamate (550 mg, 1.98 mmol, 52%) as a colorless oil. ESI-MS (EI+, m/z): 279.2 [M+H]+.

Step 2: (S)-2-Amino-N,4-dimethylpentanamide [I-21]

A mixture of (S)-benzyl 4-methyl-1-(methylamino)-1-oxopentan-2-ylcarbamate (300 mg, 1.08 mmol) and Pd/C (10%) (50 mg) in MeOH (10 mL) was stirred at rt for 2 h under hydrogen. The mixture was filtered, and the filter cake was washed with MeOH (10 mL). The filtrate was concentrated to afford (S)-2-amino-N,4-dimethylpentanamide (1-21), (152 mg, 1.05 mmol, 98%) as a colorless oil. ESI-MS (EI+, m/z): 145.3 [M+H]+. 1H-NMR (500 MHz, DMSO-d6): δ 7.80 (s, 1H), 3.10 (dd, J=5.0 Hz, 9.0 Hz, 1H), 2.57 (dd, J=3.0 Hz, 5.0 Hz, 3H), 1.81 (s, 2H), 1.66-1.69 (m, 1H), 1.34-1.39 (m, 1H), 1.16-1.22 (m, 1H), 0.81-0.87 (m, 6H).

Example 22: (S)-4-methyl-2-(phenylamino)pentanoic Acid [I-22]

Procedures and Characterization: Step 1: (S)-Benzyl 2-(cyclohexanecarboxamido)-4-methylpentanoate

To a solution of L-leucine benzyl ester p-toluenesulfonate (500 mg, 1.27 mmol), cyclohexanecarboxylic acid (244 mg, 1.91 mmol) and HATU (726 mg, 1.91 mmol) in DMF (10 mL) was added DIPEA (410 mg, 3.18 mmol) and the solution was stirred for 2 h at rt. The solution was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 2-(cyclohexanecarboxamido)-4-methylpentanoate (300 mg, 0.91 mmol, 71%) as a white solid. MS (EI+, m/z): 332.3 [M+H]+.

Step 2: (S)-2-(Cyclohexanecarboxamido)-4-methylpentanoic Acid [I-22]

To a stirred solution of (S)-benzyl 2-(cyclohexanecarboxamido)-4-methylpentanoate (200 mg, 0.60 mmol) in EtOH (10 mL) was added a catalytic amount of Pd/C (10%, 20 mg). The reaction was stirred under hydrogen atmosphere for 3 h at 50° C. The resulting solution was filtered and concentrated to afford (S)-2-(cyclohexanecarboxamido)-4-methylpentanoic acid (I-22), (100 mg, 0.41 mmol, 69%) as a white solid. MS (EI+, m/z): 242.3 [M+H]⁺. 1H-NMR (500 MHz, CD₃OD): δ 4.43 (t, J=7.5 Hz, 1H), 2.29 (td, J=8.0 Hz, 11.0 Hz, 1H), 1.74-1.85 (m, 4H), 1.63-1.72 (m, 4H), 1.43-1.49 (m, 2H), 1.26-1.36 (m, 3H), 0.96 (dd, J=6.0 Hz, 20.5 Hz, 6H).

Example 25: (S)-4-methyl-2-(phenylsulfonamido)pentanoic Acid [I-25]

Procedures and Characterization: Step 1: (S)-Benzyl 4-methyl-2-(phenylsulfonamido)pentanoate

To a solution of (S)-benzyl 2-amino-4-methylpentanoate 4-methylbenzenesulfonate (300 mg, 0.762 mmol) and Et3N (385.73 mg, 3.81 mmol) in DMF (3 mL), cooled with an ice-bath, was added benzenesulfonyl chloride (148.12 mg, 0.838 mmol). The mixture was stirred at 25° C. for 2 h. The solution was diluted with ethyl acetate (10 mL), washed with resulting solution was filtered (10 mL×3) and brine (10 mL), dried with anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product (280 mg, purity: 85%, yield: 74%) was used directly in the next step. ESI-MS (EI+, m/z): 384.1 [M+Na]+.

Step 2: (S)-4-Methyl-2-(phenylsulfonamido)pentanoic Acid [I-25]

To a solution of (S)-benzyl 4-methyl-2-(phenylsulfonamido)pentanoate (200 mg, 0.553 mmol) in EtOH (3 mL), was added Pd/C (20 mg, 10%). This reaction mixture was stirred at 50° C. for 4 h under hydrogen atmosphere. The mixture was filtered, and the filter cake was washed with MeOH (10 mL). The filtrate was concentrated to afford (S)-4-methyl-2-(phenylsulfonamido)pentanoic acid (1-25), (63.7 mg, 0.234 mmol, 100%) as a white solid. ESI-MS (EI⁺, m/z): 294.0 [M+Na]⁺. ¹H-NMR (500 MHz, DMSO-d₆) δ 12.61 (s, 1H), 8.16 (d, J=8.6 Hz, 1H), 7.79-7.73 (m, 2H), 7.62 (t, J=13 Hz, 1H), 7.56 (t, J=7.4 Hz, 2H), 3.63 (dd, J=8.5 Hz, 14.5 Hz, 1H), 1.53 (td, J=6.5 Hz, 13.5 Hz, 1H), 1.41-1.31 (m, 2H), 0.79 (d, J=6.6 Hz, 3H), 0.66 (d, J=6.5 Hz, 3H).

Example 26: (S)-4-methyl-2-(phenylamino)pentanoic Acid [I-26]

Procedures and Characterization: Step 1: (S)-Benzyl 4-methyl-2-(phenylamino)pentanoate

To a mixture of L-leucine benzyl ester p-toluenesulfonate (200 mg, 0.51 mmol), phenylboronic acid (186 mg, 1.52 mmol) and Cu(OAc)2 (462 mg, 2.54 mmol) in DCM (10 mL) was added 4A MS (1.0 g) and Et3N (155 mg, 1.52 mmol) and the mixture was stirred for 18 h at rt. The mixture was quenched with resulting solution was filtered (50 mL), extracted with EtOAc (50 mL×2), washed with resulting solution was filtered (50 mL) and brine (50 mL). The organic phase was concentrated purified by chromatography (silica, ethyl acetate/petroleum ether=1/20) to afford (S)-benzyl 4-methyl-2-(phenylamino)pentanoate (100 mg, 0.34 mmol, 66%) as colorless oil. MS (EI+, m/z): 298.2 [M+H]+.

Step 2: (S)-4-methyl-2-(phenylamino)pentanoic Acid [I-26]

To a stirred solution of (S)-benzyl 4-methyl-2-(phenylamino)pentanoate (100 mg, 0.34 mmol) in EtOH (10 mL) was added a catalytic amount of Pd/C (10%, 20 mg). The reaction was stirred under hydrogen atmosphere for 2 h at 50° C. The resulting solution was filtered and concentrated to afford (S)-4-methyl-2-(phenylamino)pentanoic acid (1-26), (30 mg, 0.15 mmol, 43%) as a white solid. MS (EI+, m/z): 208.1 [M+H]+. 1H-NMR (400 MHz, CDCl3): δ 7.23 (t, J=8.0 Hz, 2H), 6.83 (t, J=7.6 Hz, 1H), 6.66 (d, J=8.0 Hz, 2H), 3.99 (d, J=8.4 Hz, 1H), 2.87 (q, J=6.0 Hz, 1H), 1.72-1.86 (m, 2H), 1.62-1.68 (m, 1H), 0.85-1.03 (m, 6H).

Example 36: (S)-2-acetamido-4-methylpentanoic Acid [I-36]

Procedures and Characterization: Step 1: (S)-Benzyl 2-acetamido-4-methylpentanoate

To a solution of L-leucine benzyl ester p-toluenesulfonate (500 mg, 1.27 mmol), acetic acid (114 mg, 1.91 mmol) and HATU (726 mg, 1.91 mmol) in DMF (10 mL) was added DIPEA (410 mg, 3.18 mmol) and the solution was stirred for 2 h at rt. The solution was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-benzyl 2-acetamido-4-methylpentanoate (300 mg, 1.14 mmol, 89%) as a white solid. MS (EI+, m/z): 264.2 [M+H]+.

Step 2: (S)-2-Acetamido-4-methylpentanoic Acid [I-36]

To a stirred solution of (S)-benzyl 2-acetamido-4-methylpentanoate (250 mg, 0.74 mmol) in EtOH (10 mL) was added a catalytic amount of Pd/C (10%, 20 mg). The reaction was stirred under hydrogen atmosphere for 3 h at 50° C. The resulting solution was filtered and concentrated to afford (S)-2-acetamido-4-methylpentanoic acid (1-36), (100 mg, 0.57 mmol, 81%) as a white solid. MS (EI+, m/z): 174.2 [M+H]⁺. ¹H NMR (500 MHz, MeOD): δ 4.43 (dd, J=6.0 Hz, 9.5 Hz, 1H), 2.00 (s, 3H), 1.61-1.73 (m, 3H), 0.97 (dd, J=6.0 Hz, 17.5 Hz, 6H).

Example 45: (S,E)-2-(4-methoxy-4-oxobut-2-enamido)-4-methylpentanoic Acid [I-45]

Procedures and Characterization: Step 1: (S,E)-2-(4-Methoxy-4-oxobut-2-enamido)-4-methylpentanoic Acid [I-45]

To a solution of (E)-4-methoxy-4-oxobut-2-enoic acid (1.0 g, 7.69 mmol) in DCM (30 mL) was added SOCl2 (1.83 g, 15.38 mmol), and then DMF (0.1 mL). The solution was heated to 40° C. for 4 h. The solution was concentrated to dryness to afford an oil. The oil was diluted with DCM (10 mL). The solution of (S)-2-amino-4-methylpentanoic acid (1.0 g, 7.62 mmol) in acetone (20 mL) and sat. Na₂CO₃ (20 mL) solution cooled with an ice-bath was added dropwise. After 1 h, the solution was adjusted pH 2 with 6 M HCl solution, extracted with EtOAc (40×2), washed with resulting solution was filtered (80 mL×3) and brine (80 mL), dried (Na₂SO₄), filtered and concentrated in vacuo. The crude product was purified by chromatography (silica, MeOH/DCM=1/20) to afford (S,E)-2-(4-methoxy-4-oxobut-2-enamido)-4-methylpentanoic acid (1-45), (1.0 g, 4.11 mmol, 53%) as a yellow oil. ESI-MS (EI⁺, m/z): 244.2 [M+H]⁺. ¹H-NMR (400 MHz, CDCl₃): δ 7.32 (d, J=15.2 Hz, 1H), 7.05 (d, J=15.2 Hz, 1H), 6.85-6.89 (m, 2H), 7.30-7.46 (m, 1H), 3.82 (s, 1H), 1.63-1.78 (m, 3H), 0.97 (d, J=4.8 Hz, 6H).

Examples 46 and 47: (R)-2-amino-3,3-difluoro-4-methylpentanoic Acid [I-46] and (S)-2-amino-3,3-difluoro-4-methylpentanoic Acid [I-47]

Procedures and Characterization: Step 1: ethyl 2,2-difluoro-3-methylbutanoate

A mixture of ethyl 3-methyl-2-oxobutanoate (10 g, 0.069 mol) and DAST (16.8 g, 0.10 mol) was stirred at rt for 12 h. After checking by TLC, the reaction mixture was added dropwise slowly to a cold, saturated aqueous sodium bicarbonate solution. The mixture was extracted with Et2O (300 mL×2), and the organic layers were washed with brine, dried and concentrated to give a crude ethyl 2,2-difluoro-3-methylbutanoate (8.3 g) which was used directly in the next step.

Step 2: 2,2-difluoro-3-methylbutanal

To a solution of crude ethyl 2,2-difluoro-3-methylbutanoate (8.3 g) in CH2Cl2 (200 mL) was added dropwise a solution of DIBAL-H in hexanes (1.0 M, 69 mL, 69.0 mmol) at −78° C. under argon, and the mixture was stirred for 30 mins at −78° C. After checking by TLC, the reaction was quenched with saturated citric acid and extracted with Et₂O. The extract was washed with saturated citric acid, brine, dried over Na₂SO₄, and concentrated under reduced pressure to give an oily aldehyde 2,2-difluoro-3-methylbutanal (4.2 g), which was used immediately in the next step without purification.

Step 3: 2-(benzylamino)-3,3-difluoro-4-methylpentanenitrile

A solution of crude 2,2-difluoro-3-methylbutanal (4.2 g) in 50 mL of MeOH was cooled to 0° C. Acetic acid (glacial, 2.1 mL) was added drop-wise, maintaining the temperature around 0° C., followed by trimethylsilyl cyanide (4.2 mL) over a period of 15 minutes. The reaction mixture was warmed to 25° C. and stirred overnight. Cold resulting solution was filtered (200 mL) was charged into the reaction mixture and the reaction mixture was extracted with dichloromethane (2*200 mL). The dichloromethane layer was washed with resulting solution was filtered (2*100 mL), followed by brine (2*50 mL). The dichloromethane layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure to give a crude 2-(benzylamino)-3,3-difluoro-4-methylpentanenitrile (2.8 g) which was used immediately in the next step without purification. ESI-MS (EI+, m/z): 238.2 [M+H]+.

Step 4: 2-(benzylamino)-3,3-difluoro-4-methylpentanoic Acid

A solution of crude 2-(benzylamino)-3,3-difluoro-4-methylpentanenitrile (2.8 g) in 50 mL of cone, hydrochloric acid and 10 mL of HO Ac was stirred at 90° C. for 24 hrs and concentrated. The residue was purified by prep-HPLC to give 2-(benzylamino)-3,3-difluoro-4-methylpentanoic acid (513 mg) as a white solid. The pure product was purified by chiral-HPLC to give (R)-2-(benzylamino)-3,3-difluoro-4-methylpentanoic acid (80 mg) and (S)-2-(benzylamino)-3,3-difluoro-4-methylpentanoic acid (63 mg) which both were white solid. ESI-MS (EI+, m/z): 258.2 [M+H]+.

Step 5-A: (R)-2-amino-3,3-difluoro-4-methylpentanoic Acid [I-46]

To a solution of (R)-2-(benzylamino)-3,3-difluoro-4-methylpentanoic acid (80 mg, 0.31 mmol) in 20 mL of MeOH was added HCOONH4 (98 mg, 1.56 mmol) and Pd/C (100 mg) at rt. The mixture was stirred at 60° C. for 2 h. The reaction mixture was filtered and concentrated to give a crude product which was purified by reverse-phase silica-gel chromatography to give (R)-2-amino-3,3-difluoro-4-methylpentanoic acid (1-46), (23 mg, 44%) as a white solid; 1H-NMR (500 MHz, D2O): δ 4.27 (dd, J=24.0, 3.5 Hz, 1H), 2.55-2.42 (m, 1H), 1.04 (d, J=7.0 Hz, 3H), 0.993 (d, J=6.5 Hz, 3H).

Step 5-B: (S)-2-amino-3,3-difluoro-4-methylpentanoic Acid [I-47]

To a solution of (S)-2-(benzylamino)-3,3-difluoro-4-methylpentanoic acid (63 mg, 0.24 mmol) in 15 mL of MeOH was added HCOONH4 (77 mg, 1.22 mmol) and Pd/C (100 mg) at rt. The mixture was stirred at 60° C. for 2 h. The reaction mixture was filtered and concentrated to give a crude product which was purified by reverse-phase silica-gel chromatography to give (S)-2-amino-3,3-difluoro-4-methylpentanoic acid (1-47), (14 mg, 34%) as a white solid; 1H-NMR (500 MHz, D2O): δ 4.27 (dd, J=24.0, 3.5 Hz, 1H), 2.55-2.42 (m, 1H), 1.04 (d, J=7.0 Hz, 3H), 0.993 (d, J=6.5 Hz, 3H).

Example 147: (S)-2-amino-4-methyl-N-(methylsulfonyl)pentanamide Hydrochloride [I-147]

Procedures and Characterization: Step 1: (S)-tert-butyl 4-methyl-1-(methylsulfonamido)-1-oxopentan-2-ylcarbamate

To a solution of (Y)-2-(tert-butoxycarbonylamino)-4-methylpentanoic acid (1.0 g, 4.32 mmol), methanesulfonamide (452 mg, 4.75 mmol) and HATU (1.8 g, 4.75 mmol) in DMF (30 mL) was added TEA (1.3 g, 12.9 mmol) and the solution was stirred for 17 h at rt. The solution was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-tert-butyl 4-methyl-1-(methylsulfonamido)-1-oxopentan-2-ylcarbamate (130 mg, 0.42 mmol, 8.9%) as a white solid. MS (EI−, m/z): 307.0 [M−H]⁻.

Step 2: (S)-2-amino-4-methyl-N-(methylsulfonyl)pentanamide hydrochloride [I-147]

A solution of (S)-tert-butyl 4-methyl-1-(methyl sulfonamido)-1-oxopentan-2-ylcarbamate (130 mg, 0.42 mmol) in Et₂O (15 mL) was added 4 M HCl/dioxane (5 mL) was stirred for 3 h at rt. The solid was filtered to afford (S)-2-amino-4-methyl-N-(methylsulfonyl)pentanamide hydrochloride [I-147] as a white solid (32 mg, 0.13 mmol, 31%). ESI-MS (EI+, m/z): 209.1 [M+H]⁺. 1H NMR (500 MHz, CD3OD) δ 3.96 (t, J=3.0 Hz, 1H), 3.32 (s, 3H), 1.74-1.79 (m, 3H), 1.02-1.05 (m, 6H).

Example 193: (S)-2-amino-N,4,4-trimethyl-N-(methylsulfonyl)pentanamide Hydrochloride[I-193]

Procedures and Characterization: Step 1: (S)-tert-butyl 4,4-dimethyl-1-(N-methylmethylsulfonamido)-1-oxopentan-2-ylcarbamate

To a solution of (S)-2-(tert-butoxycarbonylamino)-4,4-dimethylpentanoic acid (500 mg, 1.97 mmol) in DCM (60 mL) was added HATH (900 mg, 2.36 mmol) and stirred at rt for 2 h. Then Cs₂CO₃ (1.92 g, 5.91 mmol), N-methylmethanesulfonamide (322 mg, 2.95 mmol) were added to the mixture and stirred for overnight at rt. The solution was diluted with water (200 mL) and extracted with DCM (100 mL). The organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum, the crude product was purified by chromatography (silica, ethyl acetate/petroleum ether=1/5) to afford (S)-tert-butyl 4,4-dimethyl-1-(N-methylmethylsulfonamido)-1-oxopentan-2-ylcarbamate (420 mg, 1.25 mmol, 63%) as a yellow oil. ESI-MS (EI+, m/z): 359.1 [M+Na]⁺.

Step 2: (S)-2-amino-N,4,4-trimethyl-N-(methylsulfonyl)pentanamidehydrochoride [I-193]

A solution of (S)-tert-butyl 4,4-dimethyl-1-(N-methylmethylsulfonamido)-1-oxopentan-2-ylcarbamate (420 mg, 1.25 mmol) in Et₂O (20 mL) was added 4 M HCl/dioxane (10 mL) was stirred for 17 h at rt. The solid was filtered to afford (S)-2-amino-N,4,4-trimethyl-N-(methylsulfonyl)pentanamidehydrochloride [I-193] as a white solid (250 mg, 0.13 mmol, 71%). ESI-MS (EI+, m/z): 237.1 [M+H]⁺. 1H NMR (500 MHz, DMSO) δ 8.55 (s, 3H), 4.59 (s, 1H), 3.50 (s, 3H), 3.26 (s, 3H), 1.81-1.85 (m, 1H), 1.63-1.67 (m, 1H), 0.95 (s, 9H).

Example 192: 2-amino-4-fluoro-4-methyl-N-(methylsulfonyl)pentanamide Hydrochloride [I-192]

Step 1: tert-butyl 4-fluoro-4-methyl-1-(methylsulfonamido)-1-oxopentan-2-ylcarbamate

To a solution of tert-butyl 4-fluoro-4-methyl-1-(methylsulfonamido)-1-oxopentan-2-ylcarbamate (270 mg, 1.08 mmol) in DCM (50 mL) was added HATU (451 mg, 1.19 mmol) and stirred at rt for 2 h. Then Cs₂CO₃ (1.06 g, 3.24 mmol), methanesulfonamide (206 mg, 2.17 mmol) were added to the mixture and stirred for overnight at rt. The solution was diluted with water (200 mL) and extracted with DCM (100 mL). The organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum, the crude product was purified by chromatography (silica, ethyl acetate/petroleum ether=1/5) to afford (S)-tert-butyl 4,4-dimethyl-1-(N-methylmethylsulfonamido)-1-oxopentan-2-ylcarbamate (200 mg, 0.6 mmol, 55%) as a yellow oil. ESI-MS (EI+, m/z): 344.1 [M+NH4]⁺.

Step 2: 2-amino-4-fluoro-4-methyl-N-(methylsulfonyl)pentanamide hydrochloride [I-192]

A solution of (S)-tert-butyl 4,4-dimethyl-1-(N-methylmethylsulfonamido)-1-oxopentan-2-ylcarbamate (200 mg, 0.6 mmol) in Et₂O (20 mL) was added 4 M HCl/dioxane (10 mL) was stirred for 17 h at rt. The solid was filtered to afford 2-amino-4-fluoro-4-methyl-N-(methylsulfonyl)pentanamide hydrochloride [I-192] as a white solid (89.8 mg, 0.34 mmol, 57%). ESI-MS (EI+, m/z): 227.1 [M+H]⁺. 1H NMR (500 MHz, DMSO) δ 8.44 (s, 3H), 4.02 (s, 1H), 3.25 (s, 3H), 2.16-2.25 (m, 1H), 2.03-2.10 (m, 1H), 1.43 (s, 3H), 1.38 (s, 3H).

Example 190: (S)-methyl 2-((S)-2-amino-4,4-dimethylpentanamido)-4-methylpentanoate Hydrochloride [I-190]

Procedures and Characterization: Step 1: (S)-methyl 2-((S)-2-(tert-butoxycarbonylamino)-4,4-dimethylpentanamido)-4-methylpentanoate

To a solution of (S)-2-(tert-butoxycarbonyl amino)-4,4-dim ethyl pentanoic acid (500 mg, 2.0 mmol) in DCM (80 mL) was added HATU (900 mg, 2.3 mmol) and stirred at rt for 2 h. Then Cs₂CO₃ (1.95 g, 6.0 mmol), (,S)-methyl 2-amino-4-methylpentanoate hydrochloride (555 mg, 3.0 mmol) were added to the mixture and stirred for overnight at rt. The solution was diluted with water (200 mL) and extracted with DCM (100 mL). The organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum, the crude product was purified by chromatography (silica, ethyl acetate/petroleum ether=1/5) to afford (S)-methyl 2-((S)-2-(tert-butoxycarbonylamino)-4,4-dimethylpentanamido)-4-methylpentanoate (500 mg, 1.34 mmol, 67%) as a white solid. ESI-MS (EI+, m/z): 317.2 [M−56]⁺.

Step 2: (S)-methyl 2-((S)-2-amino-4,4-dimethylpentanamido)-4-methylpentanoate Hydrochloride [I-190]

A solution of (S)-methyl 2-((S)-2-(tert-butoxycarbonylamino)-4,4-dimethylpentanamido)-4-methylpentanoate (500 mg, 1.34 mmol) in Et₂O (20 mL) was added 4 M HCl/dioxane (10 mL) was stirred for 17 h at rt. The solid was filtered to afford (S)-methyl 2-(S)-2-amino-4,4-dim ethyl pentanamido)-4-methylpentanoate hydrochloride [I-190] as a white solid (300 mg, 0.97 mmol, 73%). ESI-MS (EI+, m/z): 273.2 [M+H]⁺. 1H NMR (500 MHz, DMSO) δ 9.07-9.09 (d, J=7.5 Hz, 1H), 8.42 (s, 3H), 4.29-4.34 (m, 1H), 3.82 (m, 1H), 3.60 (s, 3H), 1.72-1.83 (m, 2H), 1.50-1.62 (m, 3H), 0.86-0.91 (m, 15H).

Example 122: (S)-methyl 2-amino-4,4-dimethylpentanoate Hydrochloride [I-122]

Procedures and Characterization: Step 1: (S)-methyl 2-amino-4,4-dimethylpentanoate Hydrochloride [I-122]

A solution of (S)-2-amino-4,4-dimethylpentanoic acid (100 mg, 0.69 mmol) in MeOH (10 mL) was added 4 M HCl/dioxane (10 mL) stirred at 80° C. for 24 h. The mixture was concentrated and the residue was beating with Et₂O to afford (S)-methyl 2-amino-4,4-dimethylpentanoate hydrochloride [I-122] as a white solid (23.6 mg, 0.12 mmol, 20%). ESI-MS (EI+, m/z): 160.1 [M+H]+. 1H-NMR (500 MHz, CD3OD): δ 4.02-4.04 (m, 1H), 3.86 (s, 3H), 1.97-2.02 (m, 1H), 1.64-1.68 (m, 1H), 1.03-1.05 (d, 9H).

Example 123: (R)-methyl 2-amino-4,4-dimethylpentanoate Hydrochloride [I-123]

Procedures and Characterization: Step 1: (R)-methyl 2-amino-4,4-dimethylpentanoate Hydrochloride [I-123]

A mixture of (R)-2-amino-4,4-dimethylpentanoic acid (50 mg, 0.34 mmol) in dry MeOH (10 mL) was added SOCl₂ (0.5 mL) stirred at rt for 17 h. The mixture was concentrated and the residue was beating with Et₂O to afford (S)-methyl 2-amino-4,4-dimethylpentanoate hydrochloride [I-123] as a white solid (34.2 mg, 0.17 mmol, 50%). ESI-MS (EI+, m/z): 160.1 [M+H]+. 1H-NMR (500 MHz, CD3OD): δ 4.02-4.04 (m, 1H), 3.86 (s, 3H), 1.97-2.02 (m, 1H), 1.64-1.68 (m, 1H), 1.03 (s, 9H).

Example 205: 2-amino-N-cyano-5,5,5-trifluoro-4-methylpentanamide Hydrochloride [I-205]

Procedures and Characterization: Step 1: 2-(tert-butoxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic Acid

A mixture of 2-amino-5,5,5-trifluoro-4-methylpentanoic acid (250 mg, 1.35 mmol), Boc₂O (353 mg, 1.62 mmol), NaOH (80 mg, 2.0 mmol) were dissolved in dioxane (10 mL) and H₂O (2 mL). The mixture was stirred at rt for 3 h. The solution was diluted with water (200 mL) and extracted with DCM (50 mL). The organic phase was washed with water (20 mL×2), and brine (10 mL), dried (Na₂SO₄), filtered and concentrated to afford crude 2-(tert-butoxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic acid (385 mg) as a colorless oil. ESI-MS (EI⁺, m/z): 307.9 [M+Na]⁺.

Step 2: 2,5-dioxopyrrolidin-1-yl 2-(tert-butoxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoate

A mixture of 2-(tert-butoxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic acid (385 mg, 1.35 mmol), 1-hydroxypyrrolidine-2,5-dione (197 mg, 1.71 mmol), DCC (353 mg, 1.71 mmol) were dissolved in DCM (15 mL). The mixture was stirred at rt for 17 h. Filtered and the filtrate was washed with brine (20 mL), dried (Na₂SO₄), filtered and concentrated to afford crude 2,5-dioxopyrrolidin-1-yl 2-(tert-butoxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoate (400 mg) as a white solid. ESI-MS (EI⁺, m/z): 282.9 [M−100]⁺.

Step 3: tert-butyl 1-cyanamido-5,5,5-trifluoro-4-methyl-1-oxopentan-2-ylcarbamate

A mixture of 2,5-dioxopyrrolidin-1-yl 2-(tert-butoxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoate (300 mg, 0.78 mmol), cyanamide (66 mg, 1.57 mmol), NaOH (156 mg, 3.9 mmol) were dissolved in THF (16 mL). The mixture was stirred at 0° C. for 0.5 h and rt for 17 h. The solution was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford tert-butyl 1-cyanamido-5,5,5-trifluoro-4-methyl-1-oxopentan-2-ylcarbamate (45 mg, 0.14 mmol) as a white solid. MS (EI+, m/z): 310.3 [M+H]⁺.

Step 4: 2-amino-N-cyano-5,5,5-trifluoro-4-methylpentanamide Hydrochloride [I-205]

A solution of tert-butyl 1-cyanamido-5,5,5-trifluoro-4-methyl-1-oxopentan-2-ylcarbamate (45 mg, 0.14 mmol) in Et₂O (20 mL) was added 4 M HCl/dioxane (10 mL) was stirred for 24 h at rt. The solution was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford 2-amino-N-cyano-5,5,5-trifluoro-4-methylpentanamide hydrochloride [I-205] (12.3 mg, 0.05 mmol, 27%) as a white solid. MS (EI+, m/z): 210.1 [M+H]⁺. 1H NMR (500 MHz, CD3OD) δ 4.06-4.09 (m, 1H), 2.43-2.65 (m, 1H), 1.67-1.85 (m, 2H), 1.18-1.22 (m, 3H).

Example 206: 2-amino-3-(1-methylcyclobutyl)propanoic Acid [I-206]

Procedures and Characterization: Step 1: N-Methoxy-N,1-dimethylcyclobutanecarboxamide

To a solution of 1-methylcyclobutanecarboxylic acid (11.6 g, 0.1 mol), NO-dimethylhydroxylamine hydrochloride (19.5 g, 0.2 mol) and HATU (42 g, 0.11 mol) in DMF (300 mL) was added TEA (30.3 g, 0.3 mol) and the solution was stirred for 17 h at rt. The solution was diluted with water (600 mL) and extracted with EtOAc (400 mL×2). The organic phase was washed with 1 N HCl, sat. NaHCO₃ and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford N-methoxy-N,1-dimethylcyclobutanecarboxamide (12.2 g, 0.07 mol, 75%) as a colorless oil. ESI-MS (EI⁺, m/z): 158.2 [M+H]⁺.

Step 2: 1-Methylcyclobutanecarbaldehyde

To a solution of N-methoxy-N,1-dimethylcyclobutanecarboxamide (2.0 g, 12.7 mmol) in dry THF (20 mL) was added 1 MLiAlH₄ (19 mL, 19 mmol) dropwise at 0° C. under N₂. The mixture was warmed to room temperature and stirred 2 hrs. The solution was quenched with sat. seignette salt slowly and extracted with Et₂O (100 mL), the organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and used for the next step.

Step 3: (Z)-tert-butyl 2-(tert-butoxycarbonylamino)-3-(1-methylcyclobutyl)acrylate

To a solution of witting reagent (2.15 g, 5.86 mmol) in dry THF (80 mL) was added t-BuONa (844 mg, 8.79 mmol) at 0° C. and stirred for 1 h. Then the solution of 1-methylcyclobutanecarbaldehyde was added and stirred at rt for 17 hrs. The solution was extracted with EtOAc (100 mL×2). The organic phase was washed with brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum. The crude product was purified by chromatography (silica, ethyl acetate/petroleum ether=1/30) to afford (Z)-tert-butyl 2-(tert-butoxycarbonylamino)-3-(1-methylcyclobutyl)acrylate (700 mg, 2.2 mmol) as a colorless oil. ESI-MS (EI⁺, m/z): 200.2 [M-56*2]⁺.

Step 4: tert-Butyl 2-(tert-butoxycarbonylamino)-3-(1-methylcyclobutyl)propanoate

A mixture of (Z)-tert-butyl 2-(tert-butoxycarbonylamino)-3-(1-methylcyclobutyl)acrylate (700 mg, 2.2 mmol) and Pd/C (10%, 100 mg) in MeOH (100 mL) was stirred at 30° C. for 17 hrs. The mixture was filtered, and the filtrate was concentrated to dryness to afford tert-butyl 2-(tert-butoxycarbonylamino)-3-(1-methylcyclobutyl)propanoate (600 mg, crude) as a colorless oil. ESI-MS (EI⁺, m/z): 158.2 [M−156]⁺.

Step 5: 2-Amino-3-(1-methylcyclobutyl)propanoic Acid [I-206]

A solution of tert-butyl 2-(tert-butoxycarbonylamino)-3-(1-methylcyclobutyl)propanoate (600 mg, crude) in Et₂O (20 mL) was added 4 MHCl/dioxane (10 mL) was stirred for 17 h at rt. The solution was concentrated to afford 2-amino-3-(1-methylcyclobutyl)propanoic acid. MS (EI⁺, m/z): 158.0 [M+H]⁺.

¹H NMR (500 MHz, D₂O) δ 3.91 (t, J=7.5 Hz, 1H), 2.06-2.02 (m, 1H), 1.88-1.64 (m, 7H), 1.15 (s, 3H).

Examples 93: S-2-amino-3-(1-methylcyclobutyl)propanoic Acid [I-93]

Procedures and Characterization:

The procedure for 2-amino-3-(1-methylcyclobutyl)propanoic acid was same as example 8

Step 6: 2-(benzyloxycarbonylamino)-3-(1-methylcyclobutyl)propanoic Acid

A mixture of 2-amino-3-(1-methylcyclobutyl)propanoic acid (300 mg, crude), CbzOSu (714 mg, 2.8 mmol) in Acetone (10 mL) and sat. NaHCO₃ (3 mL) was stirred at rt for 5 h. The solution was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford 2-(benzyloxycarbonylamino)-3-(1-methylcyclobutyl)propanoic acid (160 mg, 0.54 mmol) as a white solid. MS (EI+, m/z): 292.0 [M+H]⁺.

Step 7: (S)-2-(benzyloxycarbonylamino)-3-(1-methylcyclobutyl)propanoic Acid

2-(benzyloxycarbonylamino)-3-(1-methylcyclobutyl)propanoic acid (160 mg, 0.54 mmol) was purified by chiral-HPLC to afford (S)-2-(benzyloxycarbonylamino)-3-(1-methylcyclobutyl)propanoic acid (50 mg, 0.17 mmol) as a white solid. MS (EI+, m/z): 292.0[M+H]⁺.

Step 8: (S)-2-amino-3-(1-methylcyclobutyl)propanoic Acid [I-93]

A mixture of (S)-2-(benzyloxycarbonylamino)-3-(1-methylcyclobutyl)propanoic acid (50 mg, 0.17 mmol) and Pd/C (10%, 10 mg) in MeOH (10 mL) was stirred at rt for 1 h. The solution was purified by prep-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-2-amino-3-(1-methylcyclobutyl)propanoic acid [I-93] (2 mg, 0.01 mmol) as a white solid. MS (EI+, m/z): 292.0[M+H]⁺. 1H NMR (500 MHz, D₂O) δ 3.76-3.79 (t, 1H), 1.96-2.00 (m, 1H), 1.61-1.86 (m, 7H), 1.11 (s, 3H).

Example 204: 2-amino-3-(trimethylsilyl)propanoic Acid Hydrochloride [I-204]

Procedures and Characterization: Step 1: tert-butyl 2-(diphenylmethyleneamino)-3-(trimethylsilyl)propanoate

A solution of tert-butyl 2-(diphenylmethyleneamino)acetate (2.5 g, 8.47 mmol) in THF (20 mL) was cooled to −78° C., then, LiHMDS (8.47 mL, 8.47 mmol) was added dropwise under N₂. The solution was stirred at −78° C. for 1 h. (iodomethyl)trimethylsilane(1.8 g, 8.47 mmol) was added dropwise. The solution was stirred at −78° C. rt overnight. The solution was washed by brine (25 mL*2), dried (Na₂SO₄), concentrated and purified by chromatography (silica, ethyl acetate/petroleum ether=1/30) to afford tert-butyl 2-(diphenylmethyleneamino)-3-(trimethylsilyl)propanoate (2.3 g, 6.04 mmol, 71%) as a yellow solid. ESI-MS (EI+, m/z): 382.3 [M+H]⁺.

Step 2: 2-amino-3-(trimethylsilyl)propanoic Acid Hydrochloride [I-204]

A solution of tert-butyl 2-(diphenylmethyleneamino)-3-(trimethylsilyl)propanoate (500 mg, 1.31 mmol) in 4 M HCl/dioxane (6 mL) was stirred for 17 h at rt. DCM (80 mL) was added. The solid was filtered to afford 2-amino-3-(trimethylsilyl)propanoic acid hydrochloride [I-204] as a white solid (113 mg, 0.57 mmol, 44%). ESI-MS (EI+, m/z): 162.2 [M+H]⁺. 1H NMR (500 MHz, CD3OD) δ 13.78 (br, 1H), 8.33 (br, 1H), 3.75 (m, 1H), 1.00-1.14 (m, 2H), 0.06 (s, 9H).

Example 201: (S)-2-amino-3-(trimethylsilyl)propanoic Acid Hydrochloride [I-201]

Procedures and Characterization: Step 1: (S)-2-amino-3-(trimethylsilyl)propanoic Acid Hydrochloride [I-201]

A solution of (S)-tert-butyl 2-(diphenylmethyleneamino)-3-(trimethylsilyl)propanoate (300 mg, 0.79 mmol) in 4 M HCl/dioxane (3 mL) was stirred for 17 h at rt. DCM (40 mL) was added. The solid was filtered to afford (S)-2-amino-3-(trimethylsilyl)propanoic acid hydrochloride [I-201] as a white solid (92 mg, 0.47 mmol, 62%). ESI-MS (EI+, m/z): 162.2 [M+H]⁺. 1H NMR (500 MHz, CD3OD) δ 13.76 (br, 1H), 8.38 (br, 1H), 3.76 (m, 1H), 1.02-1.16 (m, 2H), 0.06 (s, 9H).

Example 200: (R)-2-amino-3-(trimethylsilyl)propanoic Acid Hydrochloride [I-200]

Procedures and Characterization: Step 1: (R)-2-amino-3-(trimethylsilyl)propanoic Acid Hydrochloride [I-200]

A solution of (R)-tert-butyl 2-(diphenylmethyleneamino)-3-(trimethylsilyl)propanoate (300 mg, 0.79 mmol) in 4 M HCl/dioxane (3 mL) was stirred for 17 h at rt. DCM (40 mL) was added. The solid was filtered to afford (R)-2-amino-3-(trimethylsilyl)propanoic acid hydrochloride [I-200] as a white solid (80 mg, 0.41 mmol, 52%). ESI-MS (EI+, m/z): 162.2 [M+H]⁺. 1H NMR (500 MHz, CD3OD) δ 13.77 (br, 1H), 8.33 (br, 1H), 3.76 (m, 1H), 1.02-1.14 (m, 2H), 0.06 (s, 9H).

Example 194: (S)-2-amino-4-fluoro-4-methylpentanoic Acid [I-194]

Procedures and Characterization: Step 1: (S)-2-amino-4-fluoro-4-methylpentanoic Acid [I-194]

A mixture of (S)-ethyl 2-amino-4-fluoro-4-methylpentanoate hydrochloride (65 mg, 0.31 mmol), LiOH.H₂O (29 mg, 0.69 mmol) in H₂O (2 mL) was stirred at rt for 2.5 h. Then, 1N HCl was added to adjust pH=3. The mixture was purified directly by reverse-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-2-amino-4-fluoro-4-methylpentanoic Acid [I-194] (40 mg, 0.27 mmol, 87%) as a white solid. MS (EI+, m/z): 150.3 [M+H]⁺. 1H NMR (500 MHz, CD3OD) δ 8.10 (br, 2H), 3.79 (m, 1H), 2.19-2.26 (m, 1H), 1.97-2.05 (m, 1H), 1.42 (d, Jz=3.5 Hz, 3H), 1.37 (d, Jz=4.0 Hz, 3H).

Example 94: (S)-3,3-dimethyl-1-(2H-tetrazol-5-yl)butan-1-amine [I-94]

Procedures and Characterization: Step 1: (S)-tert-butyl 1-cyano-3,3-dimethylbutylcarbamate

To a solution of (S)-tert-butyl 1-amino-4,4-dimethyl-1-oxopentan-2-ylcarbamate (500 mg, 2.1 mmol) in DMF (10 mL) was added Cyanuric chloride (450 mg, 2.5 mmol) and stirred at rt for 2 h. Then, the mixture was diluted by Brine(100 mL), extracted with ethyl acetate (50 mL), dried (Na₂SO₄) and concentrated to give crude (S)-tert-butyl 1-cyano-3,3-dimethylbutylcarbamate (500 mg) as a yellow dope. ESI-MS (EI+, m/z): 249.2 [M+Na]⁺.

Step 2: (S)-tert-butyl 3,3-dimethyl-1-(2H-tetrazol-5-yl)butylcarbamate

A mixture of (S)-tert-butyl 1-cyano-3,3-dimethylbutylcarbamate (crude 500 mg), ZnBr₂ (900 mg, 4.0 mmol), NaN₃(260 mg, 4.0 mmol) in DMF (20 mL) was stirred for 17 h at 100° C. The mixture was then diluted with Brine (200 mL), extracted with ethyl acetate (60 mL), dried (Na₂SO₄) and concentrated to give crude (S)-tert-butyl 3,3-dimethyl-1-(2H-tetrazol-5-yl)butylcarbamate (400 mg) as a yellow dope. ESI-MS (EI+, m/z): 214.3 [M+H-56]⁺.

Step 3: ((S)-3,3-dimethyl-1-(2H-tetrazol-5-yl)butan-1-amine [I-94]

A solution of (S)-tert-butyl 3,3-dimethyl-1-(2H-tetrazol-5-yl)butylcarbamate (crude 300 mg) in 4 M HCl/dioxane (3.5 mL) was stirred for 17 h at rt. Then, the solution was concentrated and purified directly by reverse phase-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford (S)-3,3-dimethyl-1-(2H-tetrazol-5-yl)butan-1-amine 2,2,2-trifluoroacetic acid salt [I-94] (30 mg, 0.11 mmol, 9% for 3 step ) as a white solid. MS (EI+, m/z): 170.2 [M+H]⁺. 1H NMR (500 MHz, CD3OD) δ 8.18 (br, 3H), 4.48 (m, 1H), 2.14 (m, 1H), 1.73 (dd, Jz=3.5, 16.5 Hz 1H), 0.72 (s, 9H).

Example 175: Synthesis of 2-amino-5,5,5-trifluoro-4-methoxypentanoic Acid [I-175]

Procedures and Characterization: Step 1: (S)-Benzyl 4-methyl-2-(phenylmethylsulfonamido)pentanoate

To a solution of 3-(benzyloxy) propan-1-ol (10.0 g, 60.24 mmol) in DMSO (100 mL) was added IBX (20.2 g, 72.29 mmol) under ice-bath. The mixture was warmed to room temperature and stirred at this temperature for 17 hrs. The reaction mixture was poured into water (300 mL) and extracted with EA (200 mL×2), the organic phase was washed with water (200 mL×3), and brine (100 mL), dried (Na₂SO₄), and the solution was concentrated and the crude was purified by SGC to obtain a light yellow liquid. (8.0 g, 81%). 1H NMR (500 MHz, CDCl3) δ 9.77 (s, 1H), 7.36-7.26 (m, 5H), 4.53 (s, 2H), 3.8-3.83 (m, 2H), 2.71-2.68 (m, 2H).

Step 2: (4-(benzyloxy)-1,1,1-trifluorobutan-2-yloxy)trimethylsilane

To a solution of 3-(benzyloxy)propanal (4.0 g, 24.4 mmol) in THF (50 mL) was added trimethyl(trifluoromethyl)silane (10.4 g, 73.2 mmol) at rt, followed by the addition of CsF (0.37 g, 2.44 mmol). The resultant solution was stirred at rt for 2 hrs. Then quenched by water (100 ml) and extracted with EA (100 ml×2), the organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated. The crude was purified by ISCO biotage to obtain (4-(benzyloxy)-1,1,1-trifluorobutan-2-yloxy)trimethylsilane as a colorless liquid. (4.5 g, 60%)

1H NMR (500 MHz, CDCl3) δ 7.38-7.29 (m, 5H), 4.51 (t, J=12 Hz, 2H), 4.23-4.19 (m, 1H), 3.59-3.57 (m, 2H), 2.04-2.01 (m, 1H), 1.78-1.73 (m, 1H), 0.13 (s, 9H).

Step 3: 4-(benzyloxy)-1,1,1-trifluorobutan-2-ol

A solution of 4-(benzyloxy)-1,1,1-trifluorobutan-2-ol (4.5 g, 14.7 mmol) in HCl solution (3 M in MeOH, 50 ml) was stirred at rt for 2 hrs. Then concentrated and purified by ISCO biotage to obtain 4-(benzyloxy)-1,1,1-trifluorobutan-2-ol (2.75 g, 80%) as a colorless liquid.

Step 4: ((4,4,4-trifluoro-3-methoxybutoxy)methyl)benzene

To a solution of 4-(benzyloxy)-1,1,1-trifluorobutan-2-ol (2.75 g, 11.75 mmol) in THF (100 ml) was added t-BuOK (1.58 g, 14.1 mmol) at 0° C. and stirred at this temperature for 30 min. Then Mel (2.17 g, 15.28 mmol) was added and stirred at rt for another 1 hour. The reaction was quenched by water (100 ml) and extracted with EA (100 ml×2), the organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated. The crude was purified by ISCO biotage to obtain ((4,4,4-trifluoro-3-methoxybutoxy) methyl) benzene (2.04 g, 70%) as a colorless liquid.

1H NMR (500 MHz, CDCl3) δ 7.38-7.29 (m, 5H), 4.53 (t, J=12 Hz, 2H), 3.78-3.74 (m, 1H), 3.66-3.57 (m, 2H), 3.5 (s, 3H), 2.03-1.96 (m, 1H), 1.78-1.57 (m, 1H).

Step 5: 4,4,4-trifluoro-3-methoxybutan-1-ol

The solution of ((4,4,4-trifluoro-3-methoxybutoxy)methyl)benzene (2.04 g, 8.23 mmol) and Pd/C (0.5 g) in MeOH (30 mL) was stirred at rt for 2 hrs, then filtered and concentrated to obtain 4,4,4-trifluoro-3-methoxybutan-1-ol as a colorless liquid. This crude was to next step directly.

Step 6: 4,4,4-trifluoro-3-methoxybutanal

To a solution of 4,4,4-trifluoro-3-methoxybutan-1-ol (1.3 g crude from last step) in DMSO (20 mL) was added IBX (2.76 g, 9.88 mmol) under ice-bath. The mixture was warmed to room temperature and stirred at this temperature for 17 hrs. The reaction mixture was poured into water (80 mL) and extracted with Et₂O (80 mL×2), the organic phase was washed with water (80 mL×3), and brine (80 mL), and the solution was to next step directly.

Step 7: 2-(benzylamino)-5,5,5-trifluoro-4-methoxypentanenitrile

To a solution of above 4,4,4-trifluoro-3-methoxybutanal in Et₂O (160 mL) was added benzylamine (2 mL), AcOH (2.0 mL) and then TMSCN (3 mL) with ice-bath. The mixture was warmed to room temperature and stirred at this temperature for 17 hrs. The solution was diluted with water (200 mL) and extracted with EA (100 mL), the organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford 2-(benzylamino)-5,5,5-trifluoro-4-methoxypentanenitrile (2.0 g, crude) as a brown thick oil which was used for the next step. ESI-MS (EI⁺, m/z):

Step 8: 2-(benzylamino)-5,5,5-trifluoro-4-methoxypentanoic Acid

A solution of 2-(benzylamino)-5,5,5-trifluoro-4-methoxypentanenitrile (2.0 g, crude) in cone. HCl (30 mL) and AcOH (10 mL) was heated to 100° C. for 17 hrs. The solution was concentrated to dryness, diluted with H₂O (100 mL) and ACN (50 mL), adjusted pH to 3-4 with sat. NaHCO₃ solution, the mixture was filtered and dried to afford 2-(benzylamino)-5,5,5-trifluoro-4-methoxypentanoic acid (0.8 g, 35% for 4 steps) as a brown solid. ESI-MS (EI⁺, m/z): [M+H]⁺.

Step 9: 2-amino-5,5,5-trifluoro-4-methoxypentanoic Acid [I-175]

A solution of 2-(benzylamino)-5,5,5-trifluoro-4-methoxypentanoic acid (300 mg, 1.03 mmol) and HCOONH₄ (650 mg, 10.3 mmol) in MeOH (10 ml) was stirred at 60° C. for 2 hrs, then filtered and concentrated. The crude was purified by reverse-phase biotage to obtain 2-amino-5,5,5-trifluoro-4-methoxypentanoic Acid [I-175] as a white solid.

1H NMR (500 MHz, methanol-r/4) δ 4.23-4.19 (m, 1H), 3.96-3.88 (m, 1H), 3.64-3.6 (m, 3H), 2.29-2.22 (m, 1H), 2.04-1.97 (m, 1H).

Example 176: 2-amino-4,4,5-trimethylhexanoic Acid [I-176]

Procedures and Characterization: Step 1: diethyl 2-(2,3-dimethylbutan-2-yl)malonate

A solution of diethyl 2-(propan-2-ylidene)malonate (2 g, 10.0 mmol) in THF (60 mL) was cooled to 0° C., followed by copper(I) iodide (2.9 g, 15.0 mmol). The mixture was stirred at 0° C. for 0.5 h. Then isopropylmagnesium bromide (1 mol/L, 30.0 mL, 30.0 mmol) was added dropwise into the above mixture at 0° C. The mixture was stirred at 0° C. for 2 h. The mixture was quenched with HCl (1 mol/L), extracted with with EtOAc (60 mL*2). The organic phase was separated, washed with water (100 mL×2), and brine (130 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford diethyl 2-(2,3-dimethylbutan-2-yl)malonate (2.4 g, 10.0 mmol, 98%) as a yellow solid. ESI-MS (EI⁺, m/z): 245.3 [M+H]⁺.

Step 2: 2-(2,3-dimethylbutan-2-yl)malonic Acid

A mixture of diethyl 2-(2, 3-dimethylbutan-2-yl)malonate acetamide (2.4 g, 10.0 mmol) and lithium hydroxide hydrate (2.1 g, 50.0 mmol) in DMSO (50 mL) and water (10 mL) was heated to 98° C. and held for 20 h. The mixture was cooled, acidified by HCl (1 mol/L), and partitioned between EtOAc (30 mL) and water (30 mL). The organic phase was separated, washed with water (50 mL×2), and brine (50 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford 2-(2,3-dimethylbutan-2-yl)malonic acid (1.8 g, 10.0 mmol, 95%) as a yellow oil. ESI-MS (EI⁺, m/z): 212.2 [M+H]⁺.

Step 3: 3, 3, 4-trimethylpentanoic Acid

A solution of 2-(2, 3-dimethylbutan-2-yl)malonic acid (1.8 g, 10.0 mmol) in DMSO (30 mL) was heated to 120° C. and held for 12 hrs. The mixture was cooled, and partitioned between EtOAc (50 mL) and water (60 mL). The organic phase was separated, washed with water (60 mL×2), and brine (60 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford 3,3,4-trimethylpentanoic acid (1.4 g, 10.0 mmol, 95%) as a yellow oil. ESI-MS (EI−, m/z): 143.2 [M−H]⁺.

Step 4: N-methoxy-N, 3, 3, 4-tetramethylpentanamide

To a solution 3,3,4-trimethylpentanoic acid (1.4 g, 10.0 mmol) in 30 mL of DMF was added N,O-dimethylhydroxylamine hydrochloride (1.2 g, 12.0 mmol) at 20° C., followed by DIEA (3.8 g, 30.0 mmol). Then HATU (5.8 g, 15.0 mmol) was added. The mixture was heated to 25° C. with stirring and held for 18 h. The reaction mixture was quenched with water, followed by methyl tert-butyl ether (50 mL*2). Phase separation, the organic layer was washed with brine (80 mL*3), dried over Na₂SO₄, filtered and concentrated in vacuum to afford N-methoxy-N,3,3,4-tetramethylpentanamide (1.5 g, 90%) as a brown oil. ESI-MS (EI⁺, m/z): 188.2 [M+H]⁺.

Step 4: 3,3,4-trimethylpentanal

To a solution N-methoxy-N, 3, 3, 4-tetramethylpentanamide (1.9 g, 0.01 mol) in 30 mL of THF was added LiAlH4 (1 g, 0.03 mol) at 0° C. The mixture was stirred at 0° C. for 1 h. The reaction mixture was quenched with water, followed by methyl tert-butyl ether (50 mL*2). Phase separation, the organic layer was washed with brine (80 mL*3), dried over Na₂SO₄ and filtered. The filtrate was contained 3, 3, 4-trimethylpentanal (1.3 g, 95%) as a colorless solution, which was used into next step directly.

Step 5: 2-(benzylamino)-4, 4, 5-trimethylhexanenitrile

To a solution of above 3, 3, 4-trimethylpentanal in methyl tert-butyl ether (120 mL) was added benzylamine (1.6 mL), AcOH (1.0 mL) and then TMSCN (1.8 mL) with ice-bath. The mixture was warmed 25° C. and stirred overnight. The solution was diluted with water (60 mL) and extracted with EtOAc (30 mL), the organic phase was washed with water (50 mL×2), and brine (50 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford 2-(benzylamino)-4, 4, 5-trimethylhexanenitrile (2 g, crude) as a brown oil which was used for the next step. ESI-MS (EI+, m/z): 245.4 [M+H]⁺.

Step 6: 2-(benzylamino)-4, 4, 5-trimethylhexanoic Acid

A solution of 2-(benzylamino)-4, 4, 5-trimethylhexanenitrile (2 g, crude) in cone. HCl (60 mL) and AcOH (10 mL) was heated to 95° C. for 18 hrs. The solution was cooled to 15° C., the pH was adjusted to 3-4 with sat. NaHCO₃ solution, the mixture was filtered and dried to afford 2-(benzylamino)-4, 4, 5-trimethylhexanoic acid (0.6 g, 2.3 mmol, 30% for 3 steps) as a white solid. ESI-MS (EI⁺, m/z): 264.4 [M+H]⁺.

2-amino-4,4,5-trimethylhexanoic Acid [I-176]

To a solution of 2-(benzylamino)-4, 4, 5-trimethylhexanoic acid (78 mg, 0.3 mmol) in 8 mL of MeOH was added HCOONH4 (0.13 g, 2.0 mmol) and Pd/C (30 mg) at rt. The mixture was stirred at 60° C. for 2 h. The reaction mixture was filtered and concentrated to give a crude product which was purified by reverse-phase silica-gel chromatography to give 2-amino-6,6,6-trifluoro-4-methylhexanoic acid [I-176] (40 mg, 90%) as a white solid; ESI-MS (EI⁺, m/z): 174.3 [M+H]⁺; 1H NMR (500 MHz, MeOD) δ 3.56 (dd, J=7.2, 4.9 Hz, 1H), 2.12 (dd, J=14.7, 4.9 Hz, 1H), 1.66-1.51 (m, 2H), 0.97 (d, j=14.9 Hz, 6H), 0.92 (dd, j=6.8, 3.6 Hz, 6H).

Example 178: 2-amino-4,4-dimethylheptanoic Acid [I-178]

Procedures and Characterization:

The procedure was the same as used in Example 176

2-amino-4,4-dimethylheptanoic acid [I-178]: ¹H NMR (500 MHz, MeOD-<d₄) δ 3.77 (t, J=6 Hz, 1H), 2.09-2.05 (m, 1H), 1.6-1.56 (m, 1H), 1.37-1.26 (m, 4H), 1.01-0.92 (m, 9H).

Example 195: 2-amino-4,4-dimethylhexanoic acid [I-195], (S)-2-amino-4,4-dimethylhexanoic acid [I-120], (R)-2-amino-4,4-dimethylhexanoic Acid [I-191]

Procedures and Characterization:

The procedure was the same as used in Example 176

2-Amino-4,4-dimethylheptanoic acid [I-195]: ¹H NMR (500 MHz, D₂O) δ 3.87 (t, J=6.0 Hz, 1H), 1.93 (dd, j=15.0 Hz, J=5.5 Hz, 1H), 1.57 (dd, J=15.0 Hz, J=6.5 Hz, 1H), 1.22-1.26 (m, 2H), 0.86 (d, (dd, j=2.0 Hz, 6H), 0.76 (t, j=7.5 Hz, 3H).

(S)-2-amino-4,4-dimethylhexanoic acid [I-120]: ¹H NMR (500 MHz, MeOD-d₄) δ 3.43 (dd, J=7.0 Hz, J=5.0 Hz, 1H), 1.95 (dd, J=15.0 Hz, J=5.0 Hz, 1H), 1.42 (dd, 7=15.0 Hz, J=7.0 Hz, 1H), 1.23-1.28 (m, 2H), 0.87 (d, (dd, J=4.5 Hz, 6H), 0.80 (t, J=7.5 Hz, 3H).

(R)-2-amino-4,4-dimethylhexanoic acid [I-191]: ¹H NMR (500 MHz, MeOD-d₄) δ 3.43 (dd, J=7.0 Hz, J=5.0 Hz, 1H), 1.95 (dd, J=15.0 Hz, J=5.0 Hz, 1H), 1.42 (dd, 7=15.0 Hz, J=7.0 Hz, 1H), 1.23-1.28 (m, 2H), 0.87 (d, (dd, J=4.5 Hz, 6H), 0.80 (t, J=7.5 Hz, 3H).

Example 177: 2-amino-6,6,6-trifluoro-4-methylhexanoic Acid [I-177]

Procedures and Characterization: Step 1: A-Methoxy-N-methyl-2-(triphenyl-15-phosphanylidene)acetamide

A mixture of (2-chloro-N-methoxy-N-methylacetamide (13.7 g, 0.1 mol) and triphenylphosphane (26.2 g, 0.1 mol) in acetonitrile (200 mL) was heated to 80° C. and held for 20 h. The mixture was cooled and concentrated to remove the solvent below 40° C. The residue was dissolved in dichloromethane (200 mL), followed by 2 N KOH (100 mL). The resulting mixture was stirred at 20° C. for 1 h. Phase separation, the organic layer was washed with brine (200 mL*3), dried over Na₂SO₄ and filtered. The filtrate was concentrated in vacuum to afford N-methoxy-N-methyl-2-(triphenyl-15-phosphanylidene) acetamide (36 g, 0.1 mol, 98%) as a yellow solid. ESI-MS (EI⁺, m/z): 364.4 [M+H]⁺.

Step 2: (E)-5,5,5-Trifluoro-N-methoxy-N, 3-dimethylpent-2-enamide

A mixture of N-methoxy-N-methyl-2-(triphenyl-15-phosphanylidene) acetamide (36.3 g, 0.1 mol) and 4,4,4-trifluorobutan-2-one (25.2 g, 0.2 mol) in tetrahydrofuran (500 mL) was heated to 70° C. and held for 7 day. The mixture was cooled and concentrated to remove the solvent below 40° C. in vacuum. The residue was purified by silica gel column (200 g, 200 300 mesh, UV 254 nm) eluting with ethyl acetate in petroleum ether from 0 to 35% to afford (E)-5,5,5-trifluoro-N-methoxy-N,3-dimethylpent-2-enamide (6 g, 0.03 mol, 28%) as a yellow oil. ESI-MS (EI⁺, m/z): 212.2 [M+H]⁺.

Step 3: 5,5,5-Trifluoro-N-methoxy-N,3-dimethylpentanamide

A mixture of (E)-5,5,5-trifluoro-N-methoxy-N,3-dimethylpent-2-enamide (6 g, 0.03 mol) and Pd/C (10%, 400 mg) in THF (100 mL) was stirred at 30° C. for 18 hrs. The mixture was filtered, and the filtrate was concentrated in vacuum to dryness to afford 5,5,5-trifluoro-N-methoxy-N,3-dimethylpentanamide (6 g, 0.03 mol, 98%) as a yellow oil. ESI-MS (EI+, m/z): 214.2 [M+H]⁺.

Step 4: 5, 5, 5-Trifluoro-3-methylpentanal

To a solution 5, 5, 5-trifluoro-N-methoxy-N, 3-dimethylpentanamide (6 g, 0.03 mol) in 100 mL of THF was added LiAlH4 (1 g, 0.03 mol) at 0° C. The mixture was stirred at 0° C. for 1 h. The reaction mixture was quenched with water, followed by methyl tert-butyl ether (60 mL*2). Phase separation, the organic layer was washed with brine (80 mL*3), dried over Na₂SO₄ and filtered. The filtrate was contained to afford 5, 5, 5-trifluoro-3-methylpentanal (4.5 g, 95%) as a colorless solution, which was used into next step directly.

Step 5: 2-(Benzylamino)-6,6,6-trifluoro-4-methylhexanenitrile

To a solution of above 5, 5, 5-trifluoro-3-methylpentanal in methyl tert-butyl ether (200 mL) was added benzylamine (5 mL), AcOH (4.0 mL) and then TMSCN (5 mL) with ice-bath. The mixture was warmed 20° C. and stirred overnight. The solution was diluted with water (100 mL) and extracted with EtOAc (100 mL), the organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford 2-(benzylamino)-6,6,6-trifluoro-4-methylhexanenitrile (6 g, crude) as a brown oil which was used for the next step. ESI-MS (EI+, m/z): 271.3 [M+H]⁺.

Step 6: 2-(Benzylamino)-6,6,6-trifluoro-4-methylhexanoic Acid

A solution of 2-(benzylamino)-6,6,6-trifluoro-4-methylhexanenitrile (3 g, crude) in cone. HCl (100 mL) and AcOH (20 mL) was heated to 100° C. for 17 hrs. The solution was cooled to 15° C., the pH was adjusted to 3-4 with sat. NaHCO₃ solution, the mixture was filtered and dried to afford 2-(benzylamino)-6,6,6-trifluoro-4-methylhexanoic acid (1 g, 13.4 mmol, 33% for 3 steps) as a white solid. ESI-MS (EI⁺, m/z): 290.3 [M+H]⁺.

2-Amino-6,6,6-trifluoro-4-methylhexanoic Acid [I-177]

To a solution of 2-(benzylamino)-6,6,6-trifluoro-4-methylhexanoic acid (88 mg, 0.31 mmol) in 8 mL of MeOH was added HCOONH₄ (0.13 g, 2.0 mmol) and Pd/C (30 mg) at rt. The mixture was stirred at 60° C. for 2 h. The reaction mixture was filtered and concentrated to give a crude product which was purified by reverse-phase silica-gel chromatography to give 2-amino-6,6,6-trifluoro-4-methylhexanoic Acid [I-177] (45 mg, 84%) as a white solid; ESI-MS (EI⁺, m/z): 200.2 [M+H]⁺; 1H NMR (500 MHz, DMSO) δ 3.15 (d, J=5.7 Hz, 1H), 2.39-2.24 (m, 1H), 2.19-1.96 (m, 2H), 1.82-1.66 (m, 1H), 1.63-1.35 (m, 1H), 0.98 (dd, J=16.5, 6.2 Hz, 3H).

Example 179: (S)-2-Amino-5-fluoro-4-(fluoromethyl)pentanoic Acid [I-179]

Procedures and Characterization: Step 1: 5-(Benzyloxymethyl)-2,2-dimethyl-1,3-dioxane

To a solution of (2, 2-dimethyl-1,3-dioxan-5-yl)methanol (0.29 g, 2.0 mmol) in DMF (10 mL) was added NaH (60% in oil, 0.12 g, 3.0 mmol) at 0° C. The mixture was stirred at 0° C. for 0.2 hours. Then (bromomethyl) benzene (0.45 g, 2.6 mmol) was added. The mixture was warmed to 10° C. for 3 h and held for 18 h. The reaction mixture was quenched with ice-water, followed by EtOAc (60 mL). Phase separation, the organic layer was washed with brine (60 mL*3), dried over Na₂SO₄ and filtered. The filtrate was concentrated and the residue was purified by silica gel column (20 g, UV 254 nm eluting with EtOAc in PE from 10% to 50%) to afford 5-(benzyloxymethyl)-2,2-dimethyl-1,3-dioxane (1), (0.46 g, 0.2 mol, 95%) as a colorless oil. ESI-MS (EI⁺, m/z): 237.3 [M+H]⁺.

Step 2: 2-(Benzyloxymethyl)propane-1,3-diol

To a solution of 5-(benzyloxymethyl)-2,2-dimethyl-1,3-dioxane (930 mg, 3.94 mmol) in MeOH (20 mL) was added 3N aqueous HCl (2 mL). The mixture was stirred at 50° C. for 2 hours. The reaction mixture was concentrated and diluted with DCM (20 mL), washed by brine (15 mL), dried and evaporated to give the crude colorless oil (780 mg, 100%). ESI-MS (EI⁺, m/z): 197 [M+H]⁺.

Step 3: ((3-Fluoro-2-(fluoromethyl)propoxy)methyl)benzene

To a pre-cooled solution of 2-(benzyloxymethyl)propane-1,3-diol (780 mg, 3.94 mmol) in DCM (20 mL) was added DAST (1.9 g, 11.8 mmol) drop wise at −78° C. The mixture was stirred at 20° C. for 24 hours. The reaction mixture was quenched by sat. NaHCO₃ aqueous (10 mL) at -78° C. DCM phase was separated and washed with brine, dried by MgSO₄, filtered through a short silica gel pad and then concentrated to give the crude colorless oil (800 mg, 100%). ESI-MS (EI⁺, m/z): 223 [M+Na]⁺. NMR (500 MHz, CDCl₃) δ 7.37-7.28 (m, 5H), 4.65-4.57 (m, 2H), 4.55-4.48 (m, 4H), 3.57 (d, J=6.2 Hz, 2H), 2.50-2.34 (m, 1H).

Step 4: 3-Fluoro-2-(fluoromethyl)propan-1-ol

To a pre-cooled solution of ((3-fluoro-2-(fluoromethyl)propoxy)methyl)benzene (800 mg, 3.94 mmol) in DCM (20 mL) was added BCl₃/toluene (1M, 6 mL, 6.0 mmol) drop wise at -78° C. The mixture was stirred at -78-0° C. for 2 hours. The reaction mixture was quenched by H₂O (0.5 mL) at -78° C. DCM phase was dried by MgSO₄, filtered and the solution (about 20 mL) was used for next step directly.

Step 5: 3-Fluoro-2-(fluoromethyl)propyl trifluoromethanesulfonate

To a pre-cooled solution of 3-fluoro-2-(fluoromethyl)propan-1-ol (8 mL solution from step 4, 1.6 mmol) was added py (380 mg, 4.8 mmol) then Tf₂O (1.36 g, 4.8 mmol) drop wise at -40° C. The mixture was stirred at -30° C. for 1 hour. The reaction mixture was quenched by brine (20 mL) at -40° C. DCM phase was separated and dried by MgSO₄, filtered and then concentrated to give the crude tan oil (200 mg, 51%) which was used for next step directly.

Step 6: tert-Butyl 2-(diphenylmethyleneamino)-5-fluoro-4-(fluoromethyl)pentanoate

To a pre-cooled solution of tert-butyl 2-(diphenylmethyleneamino)acetate (944 mg, 3.2 mmol) in THF (20 mL) was added LDA (2.5M in THF/toluene/hexane, 1.28 mL, 3.2 mmol) at −78° C. in 25 mins. The mixture was stirred at this temperature for 10 mins. A solution of 3-fluoro-2-(fluoromethyl)propyl trifluoromethanesulfonate (200 mg, 0.82 mmol) in THF (2 mL) was added drop wise at -78° C. The reaction mixture was placed just above the cooling bath and stirred for another 1 h. The reaction mixture was quenched by sat. NH₄Cl aqueous (20 mL), extracted with MTBE (30 mL*2), washed with H₂O, brine (50 mL each), dried and concentrated to give the crude which was purified by chorography (silica gel, PE to 5% EA/PE) twice to give desired product (22 mg, 6.9%) as white solid. ESI-MS (EI⁺, m/z): 388 [M+H]⁺. ¹H NMR (500 MHz, DMSO) δ 7.56-7.45 (m, 6H), 7.41 (t, J=7.4 Hz, 2H), 7.18 (d, J=6.3 Hz, 2H), 4.50-4.17 (m, 4H), 3.91 (dd, J=7.7, 5.5 Hz, 1H), 2.11-1.97 (m, 1H), 1.87 (dd, J=12.7, 5.5 Hz, 2H), 1.38 (s, 9H).

Step 7: (S)-2-Amino-5-fluoro-4-(fluoromethyl)pentanoic acid hydrochloride

A solution of tert-butyl 2-(diphenylmethyleneamino)-5-fluoro-4-(fluoromethyl)pentanoate (55 mg, 0.14 mmol) in 3N HCl/MeOH (2 mL) was stirred at room temperature for 20 hours. The reaction mixture was concentrated and washed by Et₂O to give the crude solid which was dissolved in DCM/TFA (1:1, 2 mL) and stirred at room temperature for 20 hours. The reaction mixture was evaporated and washed by Et₂O to give the crude solid which was dissolved in 6NHCl (1 mL) and stirred at 80° C. for 2h. The reaction mixture was evaporated and lyophilized to give crude product which was purified by RP-biotage using 3 mM HCl/H₂O to give desired product (8.3 mg, 29%) as white solid. ESI-MS (EI⁺, m/z): 168 [M+H]⁺. 1H NMR (500 MHz, DMSO) δ 7.85 (bs, 3H), 4.48 (dd, J=48.3, 14.2 Hz, 4H), 3.46-3.36 (m, 1H), 2.47-2.26 (m, 1H), 1.78 (dt, J=14.3, 7.3 Hz, 1H), 1.63-1.53 (m, 1H).

Example 187: (S)-3-Amino-5,5-dimethyl-dihydrofuran-2(3H)-one [I-187]

Procedures and Characterization: Step 1: (S)-3-Amino-5,5-dimethyl-dihydrofuran-2(3H)-one [I-187]

To a round bottom flask containing (S)-2-amino-4-methylpent-4-enoic acid (100 mg) was added Con.HCl (1 mL) and SOCl₂(0.2 mL). The mixture was stirred at room temperature for 4 hours. The reaction mixture was concentrated and washed by Et₂O to give the crude solid which was purified by RP-biotage using 0.025% TFA/H₂O/MeCN to give desired product (20.2 mg, 11.4%) as white solid. ESI-MS (EI⁺, m/z): 130.1 [M+H]⁺. NMR (500 MHz, DMSO) δ 8.80 (bs, 3H), 4.58 (dd, J=11.2, 9.3 Hz, 1H), 2.53-2.48 (m, 1H), 2.13 (t, J=11.7 Hz, 1H), 1.45 (s, 3H), 1.40 (s, 3H).

Example 90: Synthesis of (S)-2-amino-5,5-difluoro-4,4-dimethylpentanoic Acid [I-90]

Procedures and Characterization: Step 1: Diethyl 2-(1,1-trifluoropropan-2-ylidene)malonate

TiCl₄ (65.8 mL, 600 mmol) was added dropwise to THF (1 L) with ice-bath over 20 mins, CCl₄ (30 mL) was added. To the mixture was added diethyl malonate (48.0 g, 300 mmol) and 1,1-difluoropropan-2-one (56.4 g, 600 mmol). The mixture was warmed to room temperature and stirred overnight. Pyridine (200 mL) was added dropwise over 20 mins with ice-bath, The reaction mixture was poured into water (2 L), filtered, and the filtrate was extracted with EtOAc (500 mL×2), the organic phase was washed with water (600 mL), 1 M HCl (600 mL×2), water (600 mL), sat. NaHCO₃ (600 mL) and brine (600 mL), dried (Na₂SO₄), filtered and concentrated in vacuum and purified by chromatography (silica, ethyl acetate/petroleum ether from 0% to 5%) to afford diethyl 2-(1,1-difluoropropan-2-ylidene)malonate (60.9 g, 258 mmol, 86%) as a colorless liquid. ESI-MS (EI⁺, m/z): 237.0 [M+H]⁺. ¹H NMR (500 MHz, CDCl₃): δ 6.97 (t, J=55.5 Hz, 1H), 4.25-4.33 (m, 4H), 2.03 (s, 3H), 1.29-1.34 (m, 6H).

Step 2: Diethyl 2-(1,1-difluoro-2-methylpropan-2-yl)malonate

To a mixture of diethyl 2-(1,1-difluoropropan-2-ylidene)malonate (10.0 g, 42.3 mmol) and CuI (12.1 g, 63.5 mmol) in DCM (100 mL) and THF (25 mL) was added dropwise MeMgI (42.3 mL, 130.5 mmol) at −20° C. over 1 h, The solution was poured into ice-water (200 mL) and treated with sat. NH₄Cl solution (100 mL), the mixture was stirred for 30 mins and filtered, the filtrate was extracted with DCM (100 mL), the organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford diethyl 2-(1,1-difluoro-2-methylpropan-2-yl)malonate (10.1 g, 40.2 mmol, 95%) as a brown liquid which was used for the next step. ESI-MS (EI⁺, m/z): 253.1 [M+H]⁺. ¹H-NMR (500 MHz, CDCl₃): δ 6.05 (t, J=57.5 Hz, 1H), 4.17-4.23 (m, 4H), 3.49 (s, 1H), 1.22-1.28 (m, 6H), 1.20 (s, 6H).

Step 3: 4,4-Difluoro-3,3-dimethylbutanoic Acid

A mixture of diethyl 2-(1,1-difluoro-2-methylpropan-2-yl)malonate (6.1 g, 24.2 mmol) and LiOH.H₂O (5.1 g, 121 mmol) in DMSO (50 mL) and H₂O (0.5 mL) was heated to 90° C. for 17 hrs. The mixture was diluted with water (200 mL), extracted with DCM (100 mL), the aqueous phase was adjusted pH to 3-4 with 6 M HCl solution, extracted with DCM (100 mL×2), dried (Na₂SO₄), filtered and concentrated in vacuum to afford 4,4-difluoro-3,3-dimethylbutanoic acid (3.6 g, crude) as a brown liquid. ESI-MS (EI⁺, m/z): 151.1 [M−H]⁻.

Step 4: 4,4-Difluoro-N-methoxy-N,3,3-trimethylbutanamide

To a solution of 4,4-difluoro-3,3-dimethylbutanoic acid (3.6 g, crude), N,O-dimethylhydroxylamine hydrochloride (4.6 g, 47.4 mmol) and HATU (10.8 g, 28.4 mmol) in DMF (50 mL) was added Et₃N (7.18 g, 71.1 mmol), after stirred at rt for 17 hrs. The mixture was filtered, and the filtrate was diluted with water (200 mL), extracted with Et₂O (100 mL×2), washed with water (100 mL), 1 M HCl (100 mL), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford 4,4-difluoro-N-methoxy-N,3,3-trimethylbutanamide (3.1 g, 15.9 mmol, 66%, 2 steps) as a brown liquid. ESI-MS (EI⁺, m/z): 196.0 [M+H]⁺. ¹H NMR (500 MHz, CDCl₃): δ 5.95 (t, J=57.5 Hz, 1H), 3.69 (s, 3H), 3.17 (s, 3H), 2.51 (s, 2H),1.12 (s, 6H).

Step 5: 4,4-Difluoro-3,3-dimethylbutanal

To a solution of 4,4-difluoro-N-methoxy-N,3,3-trimethylbutanamide (3.1 g, 15.9 mmol) in THF (80 mL) was added dropwise LiAlH₄ (24 mL, 24 mmol) with ice-bath. After 1 h, the mixture was quenched with citric acid solution (100 mL), the solution was extracted with Et₂O (100 mL×2), the organic phase was washed with brine (100 mL), dried (Na₂SO₄), and the solution was used for the next step.

Step 6: 2-(Benzylamino)-5,5-difluoro-4,4-dimethylpentanenitrile

To the above solution of 4,4-difluoro-3,3-dimethylbutanal in Et₂O (200 mL) was added benzylamine (3 mL), AcOH (3 mL) and then TMSCN (3 mL) with ice-bath, the solution was stirred at 0˜rt for 17 hrs, and then diluted with EtOAc (100 mL). The solution was washed with H₂O (100 mL×2) and then concentrated to afford 2-(benzylamino)-5,5-difluoro-4,4-dimethylpentanenitrile (3.2 g, crude) as a brown liquid. ESI-MS (EI⁺, m/z): 253.0 [M+H]⁺.

Step 7: 2-(Benzylamino)-5,5-difluoro-4,4-dimethylpentanoic Acid

A solution of 2-(benzylamino)-5,5-difluoro-4,4-dimethylpentanenitrile (1.8 g, crude) in cone. HCl (50 mL) and AcOH (10 mL) was heated to 100° C. for 64 hrs. The mixture was concentrated to remove the solvent, adjusted pH to 12 with 1 M NaOH solution, extracted with PE (100 mL), the aqueous phase was adjusted pH to 5-6 with 6 M HCl. The white solid was formed, filtered, and the filter cake was washed with water (50 mL), dried in vacuum to afford 2-(benzylamino)-5,5-difluoro-4,4-dimethylpentanoic acid (1.3 g, 4.80 mmol, 54%, 3 steps) as a white solid. ESI-MS (EI⁺, m/z): 272.0

Step 8: 2-Amino-5,5-difluoro-4,4-dimethylpentanoic Acid

A mixture of 2-(benzylamino)-5,5-difluoro-4,4-dimethylpentanoic acid (1.3 g, 4.80 mmol), HCOONH₄ (1.51 g, 24 mmol) and Pd/C (10%, 200 mg) in MeOH (50 mL) was heated to 60° C. for 1 h. The mixture was filtered, and the filtrate was concentrated to afford 2-amino-5,5-difluoro-4,4-dimethylpentanoic acid (1.0 g, crude) as a white solid. ESI-MS (EI⁺, m/z): 182.0

Step 9: 2-(Benzyloxycarbonylamino)-5,5-difluoro-4,4-dimethylpentanoic Acid

To a solution of 2-amino-5,5-difluoro-4,4-dimethylpentanoic acid (1.0 g, crude) and NaHCO₃ (1.27 g, 14.4 mmol) in acetone (30 mL) and H₂O (30 mL) was added CbzOSu (2.39 g, 9.6 mmol) with ice-bath. After being stirred for 17h, the mixture was adjusted pH to 3-4 with 1M HCl solution, and the solution was extracted with EtOAc (50 mL×2), washed with brine (50 mL), dried (Na₂SO₄), filtered and concentrated in vacuum, the crude product was purified by reverse-phase silica-gel chromatography and then chiral-prep-HPLC [column, CC4 4.6*250 mm 5 um; solvent, MeOH (0.2% Methanol Ammonia)] to afford 6V)-2-(benzyloxycarbonylamino)-5,5-difluoro-4,4-dimethylpentanoic acid (400 mg, 1.27 mmol, 26%, 2 steps) and (R)-2-(benzyloxycarbonylamino)-5,5-difluoro-4,4-dimethylpentanoic acid (380 mg, 1.21 mmol, 25%, 2 steps) as two colorless oils. ESI-MS (EI⁺, m/z): 316.0

Step 10: (S)-2-Amino-5,5-difluoro-4,4-dimethylpentanoic Acid

To a solution of (S)-2-(benzyl oxycarbonyl amino)-5,5-difluoro-4,4-dim ethyl pentanoic acid (400 mg, 1.27 mmol) and Pd/C (10%, 50 mg) in MeOH (30 mL) was stirred at rt for 2 hrs under hydrogen, the mixture was filtered and concentrated in vacuum and purified by reverse-phase silica-gel chromatography to afford 65)-2-amino-5,5-difluoro-4,4-dimethylpentanoic acid (115.7 mg, 0.64 mmol, 50%). ESI-MS (EI⁺, m/z): 182.0 ¹H NMR (500 MHz, MeOD-t/4): δ 5.60 (t, J=56.5 Hz, 1H), 3.97 (t, J=6.0 Hz, 1H), 2.07 (dd, J=15.5 Hz, J=5.5 Hz, 1H), 1.77 (dd, J=15.5 Hz, j=6.5 Hz, 1H), 0.96 (d, j=9.5 Hz, 6H).

Example 88: Synthesis of (S)-2-amino-5,5-difluoro-4,4-dimethylpentanoic Acid [I-88]

Procedures and Characterization: Step 1: (S)-2-(Benzylamino)-5,5-difluoro-4,4-dimethylpentanamide

To a solution of 2-(benzylamino)-5,5-difluoro-4,4-dimethylpentanenitrile (1.2 g, 4.76 mmol) in DCM (20 mL) was added dropwise to cone. H₂SO₄ (10 mL) with ice-bath over 5 mins, the mixture was warmed to room temperature and stirred for 6 hrs. The mixture was poured into ice-water (100 mL), the solution was adjusted PH to 8 9 with 10% NaOH solution, and then extracted with EtOAc (100 mL×2), the organic phase was washed with water (100 mL), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum and purified by chromatography (MeOH/DCM from 0% to 5%) and then chiral-prep-HPLC [column, CC4 4.6*250 mm 5 um; solvent, MeOH (0.2% Methanol Ammonia)] to afford (S)-2-(benzylamino)-5,5-difluoro-4,4-dimethylpentanamide (400 mg, 1.48 mmol, 31%) and (R)-2-(benzylamino)-5,5-difluoro-4,4-dimethylpentanamide (380 mg, 1.41 mmol, 30%) as two colorless liquids. ESI-MS (EI⁺, m/z): 253.0 [M+H]⁺.

Step 2: (S)-2-Amino-5,5-difluoro-4,4-dimethylpentanamide

A mixture of (S)-2-(benzyl amino)-5,5-difluoro-4,4-dim ethyl pentanamide (200 mg, 0.74 mmol), HCOONH₄ (233 mg, 3.7 mmol) and Pd/C (10%, 40 mg) in MeOH (15 mL) was heated to 60° C. for 1 h. The mixture was filtered, and the filtrate was concentrated and purified by reverse-phase silica-gel chromatography to afford (S)-2-amino-5,5-difluoro-4,4-dimethylpentanamide trifluoracetic acid (128 mg, 0.44 mmol, 59%) as a white solid. ESI-MS (EI⁺, m/z): 181.0 [M+H]⁺. ¹H-NMR (500 MHz, MeOD-d7): δ 5.66 (t, J=56.5 Hz, 1H), 3.95 (dd, J=8.0 Hz, J=5.0 Hz, 1H), 2.14 (dd, J=10.0 Hz, J=8.0 Hz, 1H), 1.83 (dd, 7=14.5 Hz, J=5.5 Hz, 1H), 1.12 (d, J=15.0 Hz, 6H).

Example 185: Synthesis of (S)-methyl 2-((S)-2-amino-5,5-difluoro-4,4-dimethylpentanamido)-4-methylpentanoate [I-185]

Procedures and Characterization: The procedure for 2-(benzyloxycarbonylamino)-5,5-difluoro-4,4-dimethylpentanoic Acid was Same as Example 90 Step 1: (S)-methyl 2-((S)-2-(benzyloxycarbonylamino)-5,5-difluoro-4,4-dimethylpentanamido)-4-methylpentanoate

The solution of (S)-2-(benzyloxycarbonylamino)-5,5-difluoro-4,4-dimethylpentanoic acid (150 mg, 0.476 mmol), HATU (199 mg, 0.524 mmol), (S)-methyl 2-amino-4-methylpentanoate hydrochloride (104 mg, 0.571 mmol) and DIPEA (123 mg, 0.952 mmol) was stirred at rt for 1 hour, then quenched by ice water (20 ml), extracted with EA (2×30 ml), dried, filtered and concentrated. The crude was purified by reverse-phase silica-gel chromatography biotage to obtain (S)-methyl 2-((S)-2-(benzyloxycarbonylamino)-5,5-difluoro-4,4-dimethylpentanamido)-4-methylpentanoate (95 mg, 45%) as a white solid. ESI-MS (EI⁺, m/z): 443.0

Step 2: (S)-methyl 2-((S)-2-amino-5,5-difluoro-4,4-dimethylpentanamido)-4-methylpentanoate

The solution of (S)-methyl 2-((S)-2-(benzyloxycarbonylamino)-5,5-difluoro-4,4-dimethylpentanamido)-4-methylpentanoate (95 mg, 0.215 mmol) and Pd/C (30 mg) in THF (5 ml) was stirred at rt for 2 hrs, then filtered, concentrated. The crude was purified by reverse-phase silica-gel chromatography biotage to obtain (S)-methyl 2-((S)-2-amino-5,5-difluoro-4,4-dimethylpentanamido)-4-methylpentanoate (45 mg, 69%) as a white solid. ESI-MS (EI⁺, m/z): 309.0

¹H NMR (500 MHz, DMSO-d6): 9.11 (d, J=7 Hz, 1H), 8.41 (s, 3H), 5.81 (t, J=56.5 Hz, 1H), 4.34-4.31 (m, 1H), 3.89-3.81 (m, 1H), 3.62 (s, 3H), 1.98-1.93 (m, 1H), 1.76-1.73 (m, 1H), 1.65-1.54 (m, 3H), 0.93-0.81 (m, 12H).

Example 184: Synthesis of (S)-methyl 2-((R)-2-amino-5,5-difluoro-4,4-dimethylpentanamido)-4-methylpentanoate [I-184]

The procedure was same as Example 90, 185.

(S)-methyl 2-((R)-2-amino-5,5-difluoro-4,4-dimethylpentanamido)-4-methylpentanoate: ESI-MS (EI⁺, m/z): 309.0

¹H NMR (500 MHz, DMSO-d6): 9.18 (d, J=7 Hz, 1H), 8.38 (s, 3H), 5.79 (t, J=56.5 Hz, 1H), 4.37-4.32 (m, 1H), 3.85-3.78 (m, 1H), 3.58 (s, 3H), 1.97-1.92 (m, 1H), 1.77-1.72 (m, 1H), 1.61-1.51 (m, 3H), 0.94-0.82 (m, 12H).

Example 145: Synthesis of (2S,4R)-2-amino-5,5,5-trifluoro-4-methylpentanoic Acid, (2R,4S)-2-amino-5,5,5-trifluoro-4-methylpentanoic Acid, (2R,4R)-2-amino-5,5,5-trifluoro-4-methylpentanoic Acid and (2S,4S)-2-amino-5,5,5-trifluoro-4-methylpentanoic Acid: [3d; I-145]; [3c; I-146]; [3a; I-167]; [3b; I-250]

Procedures and Characterization: Step 1: Synthesis of (2S,4R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic Acid, (2R,4S)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic Acid, (2R,4R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic Acid and (2S,4S)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic Acid

To a solution of 2-amino-5,5,5-trifluoro-4-methylpentanoic acid (600 mg, 3.2 mmol) in Acetone (10 mL) and NaHCO₃ saturated aqueous (10 mL) was added CbzOSu (970 mg, 3.9 mmol). The mixture was stirred at rt for 3 hrs. Then EtOAc (20 mL) and H₂O (20 mL) was added, the aqueous was separated and further extracted with EtOAc (2*20 mL), combined the extracts and washed by brine (20 mL), dried by anhydrous Na₂SO₄, filtered and concentrated, the residue was purified by pre-HPLC to afford 2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic acid (750 mg) as a white solid. The pure product was purified by chiral-HPLC to give the four isomers: (2S,4R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic acid (150 mg, 15%), (2R,4S)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic acid (40 mg, 3.9%), (2R,4R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic acid (50 mg, 4.9%) and (2S,4S)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic acid (80 mg, 7.8%) which both were white solid. ESI-MS (EI+, m/z): 342.0 [M+Na]+.

Step 2-A: Synthesis of (2S,4R)-2-amino-5,5,5-trifluoro-4-methylpentanoic Acid

A solution of (2S,4R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic acid (150 mg, 0.47 mmol) and Pd/C (75 mg) in MeOH (15 mL) was stirred at rt for 3 hrs. The reaction mixture was filtered and concentrated to give (2S,4R)-2-amino-5,5,5-trifluoro-4-methylpentanoic acid (51.7 mg, 59%) as a white solid. . ESI-MS (EI⁺, m/z): 186.2 [M+H]⁺. ¹H NMR (500 MHz, MeOD): δ 3.64-3.60 (m, 1H), 2.77-2.71 (br, 1H), 2.24-2.18 (m, 1H), 1.76-1.69 (m, 1H), 1.25 (d, J=7.0 Hz, 3H).

Step 2-B: Synthesis of (2R,4S)-2-amino-5,5,5-trifluoro-4-methylpentanoic Acid

A solution of (2R,4S)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic acid (40 mg, 0.12 mmol) and Pd/C (20 mg) in MeOH (4 mL) was stirred at rt for 3 hrs. The reaction mixture was filtered and concentrated to give (2R,4S)-2-amino-5,5,5-trifluoro-4-methylpentanoic acid (13.3 mg, 60%) as a white solid. . ESI-MS (EI⁺, m/z): 186.2 [M+H]⁺. ¹H-NMR (500 MHz, MeOD): δ 3.51-3.47 (m, 1H), 2.64-2.58 (br, 1H), 2.12-2.06 (m, 1H), 1.63-1.57 (m, 1H), 1.13 (d, J=7.0 Hz, 3H).

Step 2-C: Synthesis of (2R,4R)-2-amino-5,5,5-trifluoro-4-methylpentanoic Acid

A solution of (2R,4R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-methylpentanoic acid (50 mg, 0.16 mmol) and Pd/C (25 mg) in MeOH (5 mL) was stirred at rt for 3 hrs. The reaction mixture was filtered and concentrated to give (2R,4R)-2-amino-5,5,5-trifluoro-4-methylpentanoic acid (18.0 mg, 61%) as a white solid. . ESI-MS (EI⁺, m/z): 186.1 [M+H]⁺. ¹H NMR (500 MHz, MeOD): δ 3.51-3.47 (m, 1H), 2.46-2.44 (br, 1H), 1.95-1.87 (m, 2H), 1.11 (d, J=7.0 Hz, 3H).

Step 2-D: Synthesis of (2S,4S)-2-amino-5,5,5-trifluoro-4-methylpentanoic Acid

A solution of (2S,4S)-2-(benzyloxycarbonylammo)-5,5,5-trifluoro-4-methylpentanoic acid (80 mg, 0.25 mmol) and Pd/C (40 mg) in MeOH (8 mL) was stirred at rt for 3 hrs. The reaction mixture was filtered and concentrated to give (2S,4S)-2-amino-5,5,5-trifluoro-4-methylpentanoic acid (38.1 mg, 82%) as a white solid. . ESI-MS (EI⁺, m/z): 186.2 [M+H]⁺. ¹H-NMR (500 MHz, MeOD): δ 3.51-3.47 (m, 1H), 2.46-2.44 (br, 1H), 1.95-1.87 (m, 2H), 1.11 (d, J=7.0 Hz, 3H).

Example 128: (S)-2-amino-5,5,5-trifluoro-4,4-dimethylpentanoic acid (I-128

Procedures and Characterization:

The procedure used was the same as used in Example 187.

(S)-2-Amino-5,5,5-trifluoro-4,4-dimethylpentanoic acid: ESI-MS (EI⁺, m/z): 200.1 ¹H NMR (500 MHz, D₂O): δ 3.94 (t, J=5.5 Hz, 1H), 2.23 (dd, J=15.5 Hz, J=5.5 Hz, 1H), 1.90 (dd, J=15.5 Hz, J=6.0 Hz, 1H), 1.13 (d, J=8.5 Hz, 6H).

Example 188: (S)-Methyl 2-((R)-2-amino-5,5,5-trifluoro-4,4-dimethylpentanamido)-4-methylpentanoate [I-188]

Procedures and Characterization:

The procedure for 2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4,4-dimethylpentanoic Acid was Same as Example 90

Step 1: (S)-methyl 2-((R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4,4-dimethylpentanamido)-4-methylpentanoate

The solution of (S)-2-(benzyloxycarbonylamino)-5,5,5-difluoro-4,4-dimethylpentanoic acid (150 mg, 0.45 mmol), HATU (188 mg, 0.495 mmol), (S)-methyl 2-amino-4-methylpentanoate hydrochloride (123 mg, 0.675 mmol) and DIPEA (175 mg, 1.35 mmol) was stirred at rt for 1 hour, then quenched by ice water (20 ml), extracted with EA (2×30 ml), dried, filtered and concentrated. The crude was purified by reverse-phase silica-gel chromatography biotage to obtain (S)-methyl 2-((S)-2-(benzyloxycarbonylamino)-5,5-difluoro-4,4-dimethylpentanamido)-4-methylpentanoate (120 mg, 58%) as a white solid. ESI-MS (EI⁺, m/z): 461.0

Step 2: (S)-methyl 2-((R)-2-amino-5,5,5-trifluoro-4,4-dimethylpentanamido)-4-methylpentanoate

The solution of (S)-methyl 2-((S)-2-(benzyloxycarbonylamino)-5,5,5-difluoro-4,4-dimethylpentanamido)-4-methylpentanoate (120 mg, 0.26 mmol) and Pd/C (30 mg) in THF (10 ml) was stirred at rt for 2 hrs, then filtered, concentrated. The crude was purified by reverse-phase silica-gel chromatography biotage to obtain (S)-methyl 2-((S)-2-amino-5,5,5-trifluoro-4,4-dimethylpentanamido)-4-methylpentanoate (49 mg, 57%) as a white solid. ESI-MS (EI⁺, m/z): 326.0

¹H NMR (500 MHz, MeOD-d4): 4.47 (t, J=7.5 Hz, 1H), 3.99-3.97 (m, 1H), 3.77 (s, 3H), 2.33-2.28 (m, 1H), 1.95-1.91 (m, 1H), 1.69-1.68 (m, 3H), 1.24-1.17 (m, 6H), 1.00-0.94 (m, 6H).

Example 189: (S)-methyl 2-((S)-2-amino-5,5,5-trifluoro-4,4-dimethylpentanamido)-4-methylpentanoate [I-189]

Synthetic Scheme:

The procedure used was the same as used in Example 188.

Procedures and Characterization: Example 189: (S)-methyl 2-((S)-2-amino-5,5,5-trifluoro-4,4-dimethylpentanamido)-4-methylpentanoate [I-189]

¹H NMR (500 MHz, MeOD-d4): 4.52 (t, J=7.5 Hz, 1H), 4.02-3.99 (m, 1H), 3.73 (s, 3H), 2.35-2.30 (m, 1H), 1.95-1.91 (m, 1H), 1.78-1.67 (m, 3H), 1.25 (s, 3H), 1.17 (s, 3H), 1.01-0.97 (m, 6H).

Example 108: (S)-2-amino-6-fluorohexanoic Acid [I-108]

Example 109: (R)-2-Amino-6-fluorohexanoic Acid [I-109]

Procedures and Characterization:

Step 1: tert-Butyl 2-(diphenylmethyleneamino)-6-fluorohexanoate

A mixture of 1-fluoro-4-iodobutane (2.0 g, 9.90 mmol), tert-butyl 2-(diphenylmethyleneamino)acetate (2.43 g, 8.25 mmol), TBAB (266 mg, 0.83 mmol) and KOH (aq. 50%) (10 mL) in DCM (10 mL) and toluene (25 mL) was stirred for 16 h at 50° C. The solution was purified by SGC (silica, ethyl acetate/petroleum ether=1/5) to afford (tert-butyl 2-(diphenylmethyleneamino)-6-fluorohexanoate (0.91 g, 2.47 mmol, 30%) as colorless oil. MS (EI+, m/z): 370.2 [M+H]⁺.

Step 2: (S)-2-Amino-6-fluorohexanoic Acid [I-108]

A solution of (S)-tert-butyl 2-(diphenylmethyleneamino)-6-fluorohexanoate (360 mg, 0.97 mmol) in dioxane (10 mL) and HCl (aq. 6M) was stirred for 16 h at rt. The mixture was extracted with ether and water. The water layer was extracted with EA after adjusting pH to 3-4. The org. layer was concentrated to afford (S)-2-amino-6-fluorohexanoic Acid [I-108] as white solid (125 mg, 0.84 mmol, 86%). ESI-MS (EI+, m/z): 150.3 [M+H]⁺. 1H NMR (500 MHz, D2O) δ 4.469 (t, J=6.0 Hz, 1H), 4.351 (t, J=6.0 Hz, 1H), 3.950 (t, J=6.0 Hz, 1H), 1.904-1.820 (m, 2H), 1.690-1.588 (m, 2H), 1.456-1.388 (m, 2H).

Step 2: (R)-2-Amino-6-fluorohexanoic Acid [I-109]

A solution of (R)-tert-butyl 2-(diphenylmethyleneamino)-6-fluorohexanoate (300 mg, 0.81 mmol) in dioxane (10 mL) and HCl (aq. 6M) was stirred for 16 h at rt. The mixture was extracted with ether and water. The water layer was extracted with EA after adjusting pH to 3-4. The org. layer was purified by HPLC to afford (R)-2-amino-6-fluorohexanoic Acid [I-109] as white solid (35 mg, 0.23 mmol, 29%). ESI-MS (EI+, m/z): 150.2 [M+H]⁺. 1H NMR (500 MHz, D2O) δ 4.505 (t, J=6.0 Hz, 1H), 4.410 (t, J=6.0 Hz, 1H), 3.823 (t, J=6.0 Hz, 1H), 1.906-1.827 (m, 2H), 1.722-1.639 (m, 2H), 1.485-1.399 (m, 2H).

Example 198: methyl 2-amino-5,5,5-trifluoro-4-(trifluoromethyl)pentanoate (I-198)

Procedures and Characterization: Step 1: 4,4,4-Trifluoro-N-methoxy-N-methyl-3-(trifluoromethyl)but-2-enamide

To a stirred solution of Hexafluoroacetone trihydrate (30 g, 136 mmol) was added H₂SO₄ (100 mL, cone.) dropwised slowly over 1 h, and the gaseous Hexafluoroacetone was introduced to the solution of N-methoxy-N-methyl-2-(tri phenyl phosphoranylidene)-acetamide (10 g, 27.5 mmol) in THF (200 mL). The mixture was stirred at room temperature for 16 hrs. Then Petroleum Ether (200 mL) was added, the white precipitate was filtered off. The filtrate was concentrated, the residue was purified by silica gel chromatography (Petroleum Ether/Ethyl Acetate=5/13/1) to afford 4,4,4-trifluoro-N-methoxy-N-methyl-3-(trifluoromethyl)but-2-enamide (6.2 g, 24.7 mmol, 90%) as a slight oil. ESI-MS (EI⁺, m/z): 252.1[M+H]⁺. ¹H NMR (500 MHz, CDCl₃): δ 7.15 (s, 1H), 3.67 (s, 3H), 3.26 (s, 3H).

Step 2: 4,4,4-Trifluoro-N-methoxy-N-methyl-3-(trifluoromethyl)butanamide

A mixture of 4,4,4-trifluoro-N-methoxy-N-methyl-3-(trifluoromethyl)but-2-enamide (4.5 g, 17.9 mmol), Pd(OH)₂/C (620 mg ) in MeOH (100 mL) was stirred at room temperature under hydrogen atmosphere for 16 hrs. Then filtered and concentrated to afford 4,4,4-trifluoro-N-methoxy-N-methyl-3-(trifluoromethyl)butanamide (1.8 g, 7.1 mmol, 40%) as a slight oil. ESI-MS (EI⁺, m/z): 254.1[M+H]⁺.

Step 3: 4,4,4-Trifluoro-3-(trifluoromethyl)butanal

To a solution of 4,4,4-trifluoro-N-methoxy-N-methyl-3-(trifluoromethyl)butanamide (1.8 g, 7.1 mmol) in THF (50 mL) was added dropwise LiAlH₄ (8.5 mL, 8.5 mmol) with ice-bath, after 1 h, the mixture was quenched with citric acid solution (100 mL), the solution was extracted with Et₂O (100 mL×2), the organic phase was washed with brine (100 mL), dried (Na₂SO₄), and the solution was used for the next step.

Step 4: 2-(Benzylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanenitrile

To the above solution of 4,4,4-trifluoro-3-(trifluoromethyl)butanal in Et₂O (200 mL) was added benzylamine (2 mL), AcOH (2 mL) and then TMSCN (2 mL) with ice-bath, the solution was stirred at 0 rt for 17 hrs, and then diluted with EtOAc (100 mL). The solution was washed with H₂O (100 mL×2) and then concentrated to afford 2-(benzylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanenitrile (2.1 g, crude) as a brown liquid. ESI-MS (EI⁺, m/z): 311.2 [M+H]⁺.

Step 5: 2-(Benzylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic Acid

A solution of 2-(benzylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanenitrile (2.1 g, crude) in cone. HCl (50 mL) and AcOH (10 mL) was heated to 100° C. for 40 hrs. The mixture was concentrated to remove the solvent, adjusted pH to 12 with 1 M NaOH solution, extracted with PE (100 mL), the aqueous phase was adjusted pH to 5-6 with 6 M HCl, the white solid was formed, filtered, and the filter cake was washed with water (50 mL), dried in vacuum to afford 2-(benzylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic acid (1.0 g, 3.0 mmol, 42%, 3 steps) as a white solid. ESI-MS (EI⁺, m/z): 272.0

Step 6: Methyl 2-(benzylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoate

A solution of 2-(benzylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic acid (800 mg, 2.4 mmol) in HCl/MeOH (50 mL, 2M) was heated to 75° C. for 17 hrs. The solution was concentrated and purified by prep-HPLC (Boston C18 21*250 mm 10¦Ìm Mobile phase: A: 0.1% TFA; B: ACN) to afford methyl 2-(benzylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoate (120 mg, 0.35 mmol, 15%) as a colorless oil. ESI-MS (EI⁺, m/z): 344.1 [M+H]⁺.

Step 7: Methyl 2-amino-5,5,5-trifluoro-4-(trifluoromethyl)pentanoate Trifluoracetic Acid

A mixture of methyl 2-(benzylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoate (100 mg, 0.30 mmol), HCOONH₄ (92 mg, 1.5 mmol) and Pd/C (10%, 20 mg) in MeOH (10 mL) was heated to 65° C. for 1 h. The mixture was filtered, and the filtrate was concentrated and purified by reverse-phase silica-gel chromatography to afford methyl 2-amino-5,5,5-trifluoro-4-(trifluoromethyl)pentanoate trifluoracetic acid (76 mg, 0.21 mmol, 70%) as a white solid. ESI-MS (EI⁺, m/z): 254.1 [M+H]⁺. NMR (500 MHz, MeOD-d₄) δ 4.26 (dd, J=7.5 Hz, J=6.0 Hz, 1H), 3.91 (m, 4H), 2.49 (dd, J=8.5 Hz, J=5.0 Hz, 1H), 2.33-2.37 (m, 1H).

Example 164: (S)-2-Amino-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic Acid (I-164)

Procedures and Characterization: Step 1: 2-Amino-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic Acid

To a solution of 2-(benzylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic acid (480 mg, 1.46 mmol) and Pd(OH)₂/C (20%, 100 mg) in AcOH (15 mL) was stirred at 35° C. for 17 hrs under hydrogen. The mixture was filtered and the filtrate was concentrated in vacuum to afford 2-amino-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic acid (460 mg, crude) as a white solid. ESI-MS (EI⁺, m/z): 240.2 [M+H]⁺.

Step 2: (S)-2-(Benzyloxycarbonylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic Acid

To a solution of 2-amino-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic acid (460 mg, crude) and NaHCO₃ (368 mg, 4.38 mmol) in acetone (30 mL) and H₂O (30 mL) was added CbzOSu (727 mg, 2.92 mmol) with ice-bath. After 17 hrs, the reaction mixture was adjusted pH to 3-4 with 1 M HCl solution, and the solution was extracted with EtOAc (50 mL×2), washed with brine (50 mL), dried (N_(a2)SO₄), filtered and concentrated in vacuum, the crude product was purified by reverse-phase silica-gel chromatography and then chiral-prep-HPLC [column, CC4 4.6*250 mm 5 um; solvent, MeOH (0.2% Methanol Ammonia)] to afford (S)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic acid (27 mg, 0.072 mmol, 5%, 2 steps) and (R)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic acid (22 mg, 0.059 mmol, 4%, 2 steps) as two colorless oils. ESI-MS (E^(I+), m/z): 396.0 [M+Na]⁺.

Step 3: (S)-2-Amino-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic Acid

A mixture of (<S)-2-(benzyloxycarbonylamino)-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic acid (27 mg, 0.072 mmol) and Pd/C (10%, 5 mg) in MeOH (10 mL) was stirred at rt for 1 h. The solution was filtered and purified by reverse-phase silica-gel chromatography to afford (S)-2-amino-5,5,5-trifluoro-4-(trifluoromethyl)pentanoic Acid [I-164](8.5 mg, 0.036 mmol, 49%) as a white solid. MS (EI⁺, m/z): 240.2[M+H]⁺. ¹H NMR (500 MHz, D₂O) δ 3.74-3.80 (m, 2H), 2.88-2.31 (m, 1H), 1.91-2.20 (m, 1H).

Example 203: 2-Amino-4-cyclopentylbutanoic Acid [I-203]

Procedures and Characterization: Step 1: 2-Cyclopentylacetaldehyde

To a solution of 3-cyclopentylpropan-1-ol (2.0 g, 17.5 mmol) in DMSO (40 mL) was added IBX (7.35 g, 26.3 mmol) under ice-bath. The mixture was warmed to room temperature and stirred overnight. The reaction mixture was poured into water (200 mL) and extracted with Et₂O (100 mL×2), the organic phase was washed with water (100 mL×3), and brine (100 mL), dried (Na₂SO₄), and the solution was used for the next step.

Step 2: (Z)-tert-Butyl 2-(tert-butoxycarbonylamino)-4-cyclopentylbut-2-enoate

To a solution of the witting reagent (2.5 g, 6.8 mmol) in THF (50 mL) was added NaOt-Bu (785 mg, 8.2 mmol) with ice-bath. After 1 h, the above solution of 2-cyclopentylacetaldehyde in Et₂O (200 mL) was added. The mixture was warmed to room temperature and stirred overnight. The solution was diluted with water (200 mL) and extracted with EA (100 mL×2), the organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum and purified by chromatography (silica, ethyl acetate/petroleum ether=1/20) to afford (Z)-tert-butyl 2-(tert-butoxycarbonylamino)-4-cyclopentylbut-2-enoate (1.0 g, 3.1 mmol, 45%, 2 steps) as a colorless liquid. ESI-MS (EI⁺, m/z): 326.2 [M+H]⁺.

Step 3: tert-Butyl 2-(tert-butoxycarbonylamino)-4-cyclopentylbutanoate

A mixture of (Z)-tert-butyl 2-(tert-butoxycarbonylamino)-4-cyclopentylbut-2-enoate (240 mg, 0.74 mmol) HCOONH₄ (233 mg, 3.7 mmol) and Pd/C (10%, 30 mg) in MeOH (15 mL) was heated to reflux for 4 hrs. The mixture was filtered and concentrated, diluted with Et₂O (50 mL), washed with water (50 mL) and brine (50 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford tert-butyl 2-(tert-butoxycarbonylamino)-4-cyclopentylbutanoate (224 mg, 0.69 mmol, 93%) as a colorless liquid. ESI-MS (EI⁺, m/z): 328.2 [M+H]⁺.

Step 4: 2-Amino-4-cyclopentylbutanoic Acid

A solution of tert-butyl 2-(tert-butoxycarbonylamino)-4-cyclopentylbutanoate (224 mg, 0.69 mmol) in 6 M HCl (20 mL) and dioxane (10 mL) was heated to 70° C. for 2 hrs. The mixture was concentrated in vacuum, diluted with water (30 mL), extracted with Et₂O (20 mL×2), and the filtrate was concentrated to dryness to afford 2-amino-4-cyclopentylbutanoic acid (114.9 mg, 0.52 mmol, 81%) as a white solid. ESI-MS (EI⁺, m/z): 172.3 [M+H]⁺. ¹H NMR (500 MHz, D₂O): δ 3.91 (t, J=6.0 Hz, 1H), 1.82-1.89 (m, 2H), 1.66-1.72 (m, 3H), 1.28-1.52 (m, 6H), 1.00-1.01 (m, 2H).

Example 202: 2-Amino-5-cyclopentylpentanoic Acid [I-202]

Procedures and Characterization: Step 1: 3-Cyclopentylpropanal

To a solution of 3-cyclopentylpropan-1-ol (1.0 g, 7.8 mmol) in DMSO (20 mL) was added IBX (3.28 g, 11.7 mmol) under ice-bath. The mixture was warmed to room temperature and stirred overnight. The reaction mixture was poured into water (100 mL) and extracted with Et₂O (60 mL×2), the organic phase was washed with water (100 mL×3), and brine (100 mL), dried (Na₂SO₄), and the solution was used for the next step.

Step 2: (E)-tert-Butyl 2-(tert-butoxycarbonylamino)-5-cyclopentylpent-2-enoate

To a solution of the witting reagent (500 mg, 1.36 mmol) in THF (15 mL) was added NaOt-Bu (157 mg, 1.63 mmol) with ice-bath. After 1 h, the above solution of 3-cyclopentylpropanal in Et₂O (100 mL) was added. The mixture was warmed to room temperature and stirred overnight. The solution was diluted with water (200 mL) and extracted with EtOAc (100 mL), the organic phase was washed with water (100 mL×2), and brine (100 mL), dried (Na₂SO₄), filtered and concentrated in vacuum and purified by chromatography (silica, ethyl acetate/petroleum ether=1/20) to afford (E)-tert-butyl 2-(tert-butoxycarbonylamino)-5-cyclopentylpent-2-enoate (250 mg, 0.74 mmol, 9.5%, 2 steps) as a colorless liquid. ESI-MS (EI⁺, m/z): 340.2 [M+H]⁺.

Step 3: tert-Butyl 2-(tert-butoxycarbonylamino)-5-cyclopentylpentanoate

A mixture of 2-(tert-butoxycarbonylamino)-5-cyclopentylpent-2-enoate (250 mg, 0.74 mmol) and Pd/C (10%, 30 mg) in MeOH (15 mL) was stirred at rt for 17 hrs under hydrogen. The mixture was filtered and concentrated to afford tert-butyl 2-(tert-butoxycarbonylamino)-5-cyclopentylpentanoate (250 mg, 0.73 mmol, 99%) as a colorless liquid. ESI-MS (EI⁺, m/z): 342.2 [M+H]⁺.

Step 4: 2-Amino-5-cyclopentylpentanoic Acid

A solution of 2-(tert-butoxycarbonylamino)-5-cyclopentylpentanoate (250 mg, 0.73 mmol) in 6 M HCl (20 mL) and dioxane (10 mL) was heated to 80° C. for 5 hrs. The mixture was concentrated in vacuum, diluted with water (30 mL), extracted with Et₂O (20 mL×2), and the filtrate was concentrated to dryness to afford 2-amino-5-cyclopentylpentanoic acid (115 mg, 0.52 mmol, 71%) as a white solid. ESI-MS (EI⁺, m/z): 186.2 [M+H]⁺. ¹H NMR (400 MHz, D₂O): 5 3.84 (t, J=6.0 Hz, 1H), 1.79-1.84 (m, 2H), 1.61-1.67 (m, 3H), 1.25-1.49 (m, 8H), 0.95-0.99 (m, 2H.

Example 197: Synthesis of 2-Amino-N-cyclopentyl-3,3-difluoro-N,4-dimethylpentanamide [I-197]

Procedures and Characterization: Step 1: 2-(Benzylamino)-N-cyclopentyl-3,3-difluoro-N,4-dimethylpentanamide

A mixture of 2-(benzylamino)-3,3-difluoro-4-methylpentanoic acid (80 mg, 0.31 mmol), N-methylcyclopentanamine (62 mg, 0.62 mmol), HATU (141 mg, 0.37 mmol) and Et₃N (94 mg, 0.93) in DMF (2 mL) was stirred at rt for 3 hrs. The mixture was purified by prep-HPLC (Boston C18 21*250 mm 10¦Ìm Mobile phase: A: 0.1% TFA; B: ACN) to afford 2-(benzylamino)-N-cyclopentyl-3,3-difluoro-N,4-dimethylpentanamide (45 mg, 0.13 mmol, 43%) as a white solid. ESI-MS (EI⁺, m/z): 339.0

Step 2: 2-Amino-N-cyclopentyl-3,3-difluoro-N,4-dimethylpentanamide

A mixture of 2-(benzylamino)-N-cyclopentyl-3,3-difluoro-N,4-dimethylpentanamide (45 mg, 0.13 mmol), HCOONH₄ (41 mg, 0.65 mmol) and Pd/C (10%, 10 mg) in MeOH (5 mL) was heated to 60° C. for 1 h. The mixture was filtered, and the filtrate was concentrated and purified by reverse-phase silica-gel chromatography to afford 2-amino-N-cyclopentyl-3,3-difluoro-N,4-dimethylpentanamide (16.3 mg, 0.066 mmol, 49%) as a white solid. ESI-MS (EI⁺, m/z): 249.2 1H NMR (500 MHz, MeOD-d₄) δ 5.26 (dd, J=15.5 Hz, J=6.0 Hz, 0.5H), 5.08 (dd, J=16.5 Hz, J=5.0 Hz, 1H), 4.28-4.31 (m, 0.5H), 2.97 (d, J=48.5 Hz, 3H), 2.38 (m, 1H), 1.65-1.99 (m, 8H), 11.16 (dt, J=6.5 Hz, J=3.0 Hz, 6H).

Example 196: 2-Amino-5-fluoro-4,4-dimethylpentanoic Acid [I-196]

Procedures and Characterization: Step 1: 3-Hydroxy-N-methoxy-N,2,2-trimethylpropanamide

The mixture of 3-hydroxy-2,2-dimethylpropanoic acid (10 g, 84.7 mmol), N,O-dimethylhydroxylamine hydrochloride (16.4 g, 101.7 mmol), EDCl (24.4 g, 127.1 mmol), HOBT (17.2 g, 127.1 mmol) and DIPEA (28 mL, 169.5 mmol) in DMF (200 mL) was stirred at rt for 16 hrs. The reaction mixture was extracted with EtOAc (200 mL×3) and water (100 mL), combined the organic layers which washed with 1 N HCl (30 mL*2), 1 N NaHCO₃ (30 mL×2) and brine (50 mL), dried, concentrated to afford a residue which purified by chromatography (silica, ethyl acetate/petroleum ether=1/2) to afford 3-hydroxy-N-methoxy-N,2,2-trimethylpropanamide(6.9 g, 50%) as a colorless oil. ESI-MS (EI⁺, m/z): 162.2 [M+H]⁺.

Step 2: 3-Fluoro-N-methoxy-N,2,2-trimethylpropanamid

To a mixture of 3-hydroxy-N-methoxy-N,2,2-trimethylpropanamide (4.5 g, 27.9 mmol) in DCM (40 mL), cooled to −78° C. was added DAST (7.4 mL, 55.9 mmol) dropwise. Then stirred at rt for 1-2 h, cooled to −78° C. again, DAST (4 mL, 27.9 mmol) was added dropwise. The reaction mixture was stirred at rt for further 1 h. The reaction mixture was being cooled to −78° C., sat.NH₄Cl (15 mL) was added slowly, DCM (50 mL) was added, separated the organic layer, washed with sat.NH₄Cl (30 mL), brine (30 mL×2), dried, concentrated to give a residue which purified by chromatography (silica, ethyl acetate/petroleum ether=1/4) to afford 3-fluoro-N-methoxy-N,2,2-trimethylpropanamide (1.9 g, 28%) as a colorless oil. ESI-MS (EI⁺, m/z): 164.2 [M+H]⁺.

Step 3: 3-Fluoro-2,2-dimethylpropanal

To a mixture of 3-fluoro-N-methoxy-N,2,2-trimethylpropanamide (1.0 g, 61.3 mmol) in THF (10 mL), cooled to 0° C. was added LiAlH₄ (6.1 mL, 61.3 mmol, 1 Min THF) dropwise. Then stirred at this temperature for 0.5-1 h. Sat. NH₄Cl (10 mL) was added slowly, extracted with Et₂O (20 mL×3), washed with water (15 mL×2) and brine (15 mL), dried, used for the next step directly. ESI-MS (EI⁺, m/z): no MS.

Step 4: (Z)-tert-Butyl 2-(tert-butoxycarbonylamino)-5-fluoro-4,4-dimethylpent-2-enoate

The mixture of 3-fluoro-2,2-dimethylpropanal (about 630 mg, 6.1 mmol, Et₂O solution from above step), tert-butyl 2-(tert-butoxycarbonylamino)-2-diethoxyphosphoryl-acetate (2.25 g, 6.1 mmol) and t-BuONa (1.2 g, 12.3 mmol) in THF (15 mL) was stirred at rt for 16 hrs. Sat.NH₄Cl (15 mL) was added, extracted with EA (30 mL×3), combined with organic layers, washed with water (15 mL) and brine (15 mL), dried, concentrated to give a residue which purified by chromatography (silica, petroleum ether to DCM) to afford (Z)-tert-butyl 2-(tert-butoxycarbonylamino)-5-fluoro-4,4-dimethylpent-2-enoate (190 mg, 0.60 mmol, 8%) as a white solid. ESI-MS (EI+, m/z): 206 [M−111]⁺.

Step 5: tert-Butyl 2-(tert-butoxycarbonylamino)-5-fluoro-4,4-dimethylpentanoate

A mixture of (Z)-tert-butyl 2-(tert-butoxycarbonylamino)-5-fluoro-4,4-dimethylpent-2-enoate (190 mg, 0.60 mmol) and Pd/C (10%, 30 mg) in IP A (15 mL) was stirred at rt for 17 hrs under hydrogen. The mixture was filtered and concentrated to afford tert-butyl 2-(tert-butoxycarbonylamino)-5-fluoro-4,4-dimethylpentanoate (200 mg, crude) as a colorless liquid. ESI-MS (EI⁺, m/z): 342.2 [M+Na]⁺.

Step 6: 2-Amino-5-fluoro-4,4-dimethylpentanoic Acid Trifluoroacetic Acid

A solution of tert-butyl 2-(tert-butoxycarbonylamino)-5-fluoro-4,4-dimethylpentanoate (200 mg, crude) in 6M HCl (20 mL) and dioxane (10 mL) was heated to 50° C. for 17 hrs. The mixture was concentrated in vacuum, diluted with water (30 mL), extracted with Et₂O (20 mL×2), and the filtrate was concentrated in vacuum and purified by reverse-phase silica-gel chromatography to afford 2-amino-5-cyclopentylpentanoic acid trifluoroacetic acid (31.7 mg, 0.11 mmol, 19%) as a white solid. ESI-MS (EI⁺, m/z): 164.2 [M+H]⁺. ¹H NMR (500 MHz, D₂O): δ 4.16 (d, J=47.5 Hz, 1H), 3.97 (t, J=5.5 Hz, 1H), 2.03 (dd, J=15.5 Hz, J=5.5 Hz, 1H), 1.71 (dd, J=15.5 Hz, J=6.0 Hz, 1H), 0.91 (dd, 7=15.0 Hz, J=2.0 Hz, 6H).

Example 186: Synthesis of 2,4-Diamino-4-methylpentanoic Acid [I-186]

Procedures and Characterization: Step 1: tert-Butyl 4-(methoxy(methyl)amino)-2-methyl-4-oxobutan-2-ylcarbamate

A solution of 3-(tert-butoxycarbonylamino)-3-methylbutanoic acid (1 g, 4.61 mmol), N,O-dimethylhydroxylamine hydrochloride (536 mg, 5.53 mmol), HATU (2.26 g, 5.99 mmol), in DMF (15 mL) was added DIPEA (1.49 g, 11.53 mmol). The solution was stirred at rt for 2 hrs, Then, the mixture was diluted by brine (100 mL), extracted by EtOAc (50 mL×2). The combined the organic layers, concentrated and purified by chromatography (silica, ethyl acetate/petroleum ether=1/3) to afford tert-butyl 4-(methoxy(methyl)amino)-2-methyl-4-oxobutan-2-ylcarbamate (1.0 g, 3.8 mmol, 82%) as a colourless oil. ESI-MS (EI⁺, m/z): 261.2 [M+H]⁺.

Step 2: tert-Butyl 2-methyl-4-oxobutan-2-ylcarbamate

A solution of tert-butyl 4-(methoxy(methyl)amino)-2-methyl-4-oxobutan-2-ylcarbamate (3.8 g, 14.6 mmol) in THF (50 mL) was added LiAlH₄ (16 mL, 1 Min THF) at r.t. The solution was stirred at rt for 2 hrs, quehched by Na₂SO₄.10H₂O, filtered and washed by THF to afford tert-butyl 2-methyl-4-oxobutan-2-ylcarbamate as a yellow solution (about 14 mmol in 110 mL THF). MS (EI⁺, m/z): 146.3 [M+H-56]⁺.

Step 3: tert-Butyl 4-(benzylamino)-4-cyano-2-methylbutan-2-ylcarbamate

A solution of tert-butyl 2-methyl-4-oxobutan-2-ylcarbamate (crude about 14 mmol in 110 mL of THF) was added BnNH₂ (2.2 mL) and AcOH (2.2 mL). The solution was stirred at rt for 10 mins. TMSCN (2.2 mL) was added. The mixture was stirred at rt for 17 hrs. Then, the reaction mixture was concentrated and by chromatography (silica, ethyl acetate/petroleum ether=1/4) to afford tert-butyl 4-(benzylamino)-4-cyano-2-methylbutan-2-ylcarbamate (670 mg, 2.11 mmol, 15%) as a yellow dope. MS (EI⁺, m/z): 318.3 [M+H]⁺.

Step 4: tert-Butyl 5-amino-4-(benzylamino)-2-methyl-5-oxopentan-2-ylcarbamate

A mixture of tert-butyl 4-(benzylamino)-4-cyano-2-methylbutan-2-ylcarbamate (640 mg, 2.00 mmol), K₂CO₃ (550 mg, 3.98 mmol) in DMSO (16 mL) was added 30% H₂O₂ (0.64 mL, 5.67 mmol) and stirred for 17 hrs at r.t. Then, the reaction mixture was diluted by H₂O (200 mL), extracted by EtOAc (100 mL×2). The combined the organic layers were concentrated to afford 2-(benzylamino)-4-(tert-butoxycarbonylamino)-4-methylpentanoic acid (crude 890 mg) as a yellow dope. MS (EE-, m/z): 336.0 [M+H]⁺.

Step 5: 2-(Benzylamino)-4-(tert-butoxycarbonylamino)-4-methylpentanoic Acid

A mixture of tert-butyl 5-amino-4-(benzylamino)-2-methyl-5-oxopentan-2-ylcarbamate (crude 890 mg, about 2.0 mmol), KOH (406 mg, 7.25 mmol) in ethane-1,2-diol (9 mL) and H₂O (9 mL) was stirred for 5 hrs at 100° C. Then, the reaction mixture was diluted by brine (200 mL), extracted by THF/EA=2:1(90 mL×5), combined the organic layers, concentrated and purified by reverse-HPLC (Boston C18 21*250 mm 10 μm, Mobile phase: A: 0.1% trifluoroacetic acid; B: acetonitrile) to afford 2-(benzylamino)-4-(tert-butoxycarbonylamino)-4-methylpentanoic acid (120 mg, 0.36 mmol, 18%) as a white solid. MS (EI+, m/z): 337.3 [M+H]⁺.

Step 6: 2-Amino-4-(tert-butoxycarbonylamino)-4-methylpentanoic Acid

A mixture of 2-(benzylamino)-4-(tert-butoxycarbonylamino)-4-methylpentanoic acid (140 mg, 0.42 mmol), HCOONH₄ (132 mg, 2.1 mmol) and Pd/C (10%, 20 mg) in MeOH (15 mL) was heated to 60° C. for 1 h. The mixture was filtered, and the filtrate was concentrated and purified by reverse-phase silica-gel chromatography to afford 2-amino-4-(tert-butoxycarbonylamino)-4-methylpentanoic acid (60 mg, 0.24 mmol, 58%) as a white solid. ESI-MS (EI⁺, m/z): 247.2

Step 7: 2,4-Diamino-4-methylpentanoic Acid

A solution of 2-amino-4-(tert-butoxycarbonylamino)-4-methylpentanoic acid (60 mg, 0.24 mmol) in 6 M HCl (10 mL) and dioxane (0 mL) was stirred at rt for 17 hrs. The solution was concentrated in vacuum to afford 2,4-diamino-4-methylpentanoic acid (51.8 mg, 0.236 mmol, 97%) as a white solid. ESI-MS (EI⁺, m/z): 147.1 1H NMR (500 MHz, D₂O) δ 4.04 (dd, J=9.5 Hz, J=3.5 Hz, 1H), 2.32 (dd, J=15.0 Hz, J=9.5 Hz, 1H),1.94 (dd, J=15.0 Hz, J=3.0 Hz, 1H), 1.38 (dd, J=9.5 Hz, J=5.0 Hz, 6H).

Example 199: Synthesis of 4,4,4-Trifluoro-3-methyl-1-(2H-tetrazol-5-yl)butan-1-amine [I-199]

Procedures and Characterization: Step 1: /V-Methoxy-/V-methyl-2-(triphenyl-15-phosphanylidene)acetamide

A mixture of 2-chloro-N-methoxy-N-methylacetamide (13.7 g, 0.1 mol) and triphenylphosphane (26.2 g, 0.1 mol) in acetonitrile (200 mL) was heated to 80° C. and held for 20 hrs. The mixture was cooled and concentrated to remove the solvent below 40° C. The residue was dissolved in dichloromethane (200 mL), followed by 2 N KOH (100 mL). The resulting mixture was stirred at 20° C. for 1 h. The organic layer was washed with brine (200 mL×3), dried over Na₂SO₄ and filtered. The filtrate was concentrated in vacuum to afford N-methoxy-N-methyl-2-(triphenyl-15-phosphanylidene) acetamide (36 g, 0.1 mol, 98%) as a yellow solid. ESI-MS (EI⁺, m/z): 364.4 [M+H]⁺.

Step 2: (E)-4,4,4-Trifluoro-N-methoxy-N,3-dimethylbut-2-enamide

A mixture of A-methoxy-N-methyl-2-(triphenyl-15-phosphanylidene) acetamide (36.3 g, 0.1 mol) and 1,1,1-trifluoropropan-2-one (22.4 g, 0.2 mol) in tetrahydrofuran (500 mL) was heated to 20° C. and held for 20 hrs. The mixture was cooled and concentrated to remove the solvent below 40° C. in vacuum. The residue was purified by silica gel column (200 g, 200 300 mesh, UV 254 nm) eluting with ethyl acetate in petroleum ether from 0 to 25% to afford (E)-4,4,4-trifluoro-N-methoxy-N, 3-dimethylbut-2-enamide (19.5 g, 0.1 mol, 98%) as a yellow oil. ESI-MS (EI⁺, m/z): 198.2 [M+H]⁺.

Step 3: 4,4,4-Trifluoro-N-methoxy-N, 3-dimethylbutanamide

A mixture of (E)-4,4,4-trifluoro-N-methoxy-N, 3-dimethylbut-2-enamide (2 g, 0.01 mol) and Pd/C (10%, 200 mg) in THF (50 mL) was stirred at 26° C. for 18 hrs. The mixture was filtered, and the filtrate was concentrated in vacuum to dryness to afford 4,4,4-trifluoro-N-methoxy-N,3-dimethylbutanamide (2 g, 0.01 mol, 98%) as a yellow oil. ESI-MS (EI⁺, m/z): 200.2 [M+H]⁺.

Step 4: 4,4,4-trifluoro-3-methylbutanal

To a solution 4,4,4-trifluoro-N-methoxy-N,3-dimethylbutanamide (2 g, 0.01 mol) in 40 mL of THF was added LiAlH₄ (0.4 g, 0.01 mol) at 0° C. The mixture was stirred at 0° C. for 1 h. The reaction mixture was quenched with water, followed by methyl tert-butyl ether (30 mL×2). The organic layer was washed with brine (50 mL×3), dried over Na₂SO₄ and filtered. The filtrate was contained to afford 4,4,4-trifluoro-3-methylbutanal (1.4 g, crude) as a colorless solution, which was used into next step directly.

Step 5: 2-(Benzylamino)-5,5,5-trifluoro-4-methylpentanenitrile

To a solution of above 4,4,4-trifluoro-3-methylbutanal in methyl tert-butyl ether (100 mL) was added benzylamine (1.5 mL), AcOH (1.0 mL) and then TMSCN (1.5 mL) with ice-bath. The mixture was warmed 20° C. and stirred overnight. The solution was diluted with water (30 mL) and extracted with EtOAc (30 mL). The organic phase was washed with water (30 mL×2), and brine (50 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford 2-(benzylamino)-5,5,5-trifluoro-4-methyl pentanenitrile (2.6 g, crude) as a brown oil which was used for the next step. ESI-MS (EI⁺, m/z): 257.3 [M+H]⁺.

Step 6: A-Benzyl-4,4,4-trifluoro-3-methyl-1-(2H-tetrazol-5-yl)butan-1-amine

To a solution of 2-(benzylamino)-5,5,5-trifluoro-4-methylpentanenitrile (0.3 g, crude) in DMF (10 mL) was added NH₄Cl (0.15 g, 0.003 mol) and NaN₃ (0.21 g, 0.003 mol) was heated to 95° C. for 18 hrs. The solution was cooled to 15° C. and extracted with EtOAc (20 mL), the organic phase was washed with water (20 mL×2), and brine (20 mL), dried (Na₂SO₄), filtered and concentrated in vacuum to afford N-benzyl-4,4,4-trifluoro-3-methyl-1-(2H-tetrazol-5-yl)butan-1-amine (0.1 g, 0.5 mmol, 33% for 3 steps) as a white solid. ESI-MS (EI⁺, m/z): 300.3 [M+H]⁺.

4,4,4-Trifluoro-3-methyl-1-(2H-tetrazol-5-yl)butan-1-amine Trifluoracetic Acid

To a solution of A-benzyl-4,4,4-trifluoro-3-methyl-1-(2H-tetrazol-5-yl)butan-1-amine (160 mg, 0.54 mmol) in MeOH (15 mL) was added HCOONH₄ (0.17 g, 2.7 mmol) and Pd/C (30 mg) at rt. The mixture was stirred at 60° C. for 2 hrs. The reaction mixture was filtered and concentrated to give a crude product which was purified by reverse-phase silica-gel chromatography to give 4,4,4-trifluoro-3-methyl-1-(2H-tetrazol-5-yl)butan-1-amine trifluoracetic acid (72.8 mg, 0.23 mmol, 42%) as a white solid; ESI-MS (EI⁺, m/z): 210.2 [M+H]⁺; 1H NMR (500 MHz, DMSO-d₆) δ 4.67-4.93 (m, 1H), 2.31-2.41 (m, 1H), 2.00-2.12 (m, 2H), 0.99 (dd, J=16.8, j=6.4 Hz, 6H).

Example 210 Western Blot Assay

This screening assay measured test compound activity in vitro on GATOR2/Sestrin2 complexes purified via immunoprecipitation of stably expressed FLAG-WDR24 from HEK293T cells. HEK293T cells (293 Ts) were engineered to stably express N-terminally tagged FLAG-WDR24 via transduction by lentivirus. Lentiviruses were produced by co-transfection of the lentiviral transfer vector pLJM60 with the ΔVPR envelope and CMV VSV-G packaging plasmids into HEK-293T cells using the XTremeGene 9 transfection reagent (Roche Diagnostics). The media was changed 24 hours post-transfection to Dulbecco's Modified Eagle's media (DMEM) supplemented with 30% Inactivated Fetal Serum. The virus-containing supernatants were collected 48 and 72 hours after transfection and passed through a 0.45 μm filter to eliminate cells. Target cells in 6-well tissue culture plates were infected in media containing 8 μg/mL polybrene and spin infections were performed by centrifugation at 2,200 rpm for 1 hour. Twenty-four hours after infection, the virus was removed and the cells selected with the appropriate antibiotic. Cells were then grown in DMEM supplemented with 10% fetal bovine serum and antibiotics.

To screen for leucine mimetic compounds, 2,000,000 FLAG-WDR24 expressing 293T cells were plated in a 10 cm tissue culture plate. Seventy-two hours later, cells were placed in standard RPMI media formulated with no amino acids and supplemented with 5 mM Glucose (−AA RPMI, US Biological Life Sciences) for 1 hour then subsequently lysed in lysis buffer (40 mM HEPES, 1% Triton, 10 mM sodium β-glycerophosphate, 10 mM sodium pyrophosphate, 2.5 mM MgCl2 and protease inhibitors). To isolate the FLAG-WDR24/endogenous-Sestrin2 complex, crude lysate (equivalent to 2-4 mg of total protein) in a volume of 1 ml was subjected to immunoprecipitation with 30 μl of anti-flag resin (SIGMA) for 2 hours at 4° C., washed twice in cold lysis buffer plus 0.5M NaCl and resuspended in 1 ml of cold cytosolic buffer (40 mM HEPES pH 7.4, 140 mM KCl, 10 mM NaCl, 2.5 mM MgCl2, 0.1% TritonX-100). Test compounds or controls (resulting solution was filtered or leucine) were then added to each immunoprecipitation sample at various concentrations and incubated with rotation at 4° C. for 60 minutes. After the incubation period, samples were centrifuged to pellet the FLAG-WDR24/endogenous-Sestrin2 complex bound to the anti-flag resin, the supernatant was completely removed and resin was resuspended in SDS-PAGE sample buffer and boiled for 5 minutes. Samples were then processed by SDS-PAGE and western blots were performed with anti-FLAG (SIGMA) and anti-Sestrin2 (Cell Signaling Technology) antibodies as described in L. Chantranupong, et al., Cell Reports 9:1-8 (2014).

The resulting western blots were scanned and band intensities corresponding to Sestrin2 and FLAG-WDR24 were quantified using the LI-COR® imaging platform. To determine the amount of Sestrin2 bound to GATOR2 for each condition, the band intensity for Sestrin2 was normalized to the band intensity of FLAG-WDR24. For every batch of compounds tested, a negative control (resulting solution was filtered) and a positive control (leucine, 25 μM, SIGMA) were also performed. The depletion of bound endogenous Sestrin2 to FLAG-WDR24 by leucine was normalized to represent 100% activity. Compounds were assayed in duplicate and activity of each compound was quantified as percent of leucine activity and averaged. Repeated attempts of the assay resulted in a standard deviation of 20% in the average activity of leucine compared to water; therefore, test compounds that reduce the amount of Sestrin2 bound to GATOR2 by at least 40% at 25 μM in duplicate were considered statistically significant and were characterized as leucine mimetics. Some compounds increased the amount of Sestrin2 bound to FLAG-WDR24. Compounds that increased the amount of Sestrin2 bound to GATOR2 by more than 40% (represented as less than −40% of leucine activity) were characterized as leucine antagonists.

Example 211. Method of Identifying Compounds that Mimic or Antagonize the Activity of Leucine Upon Sestrin2 and the Sestrin2/GATOR2 Interaction

Introduction

Sestrin1 and Sestrin2 interact with GATOR2 via the GATOR2 components WDR24 and Seh1L under insufficient leucine levels. Under leucine sufficient conditions, leucine directly binds Sestrin2 inducing the disassociation of Sestrin2 from GATOR2. The goal of the following methods is to identify compounds that mimic the effect of leucine in binding to Sestrin2 and disrupting the Sestrin2/GATOR2. In addition, the methods identify compounds that antagonize leucine binding to Sestrin2 and prevent the disassociation of Sestrin2 from GATOR2 in response to leucine.

Method 1 (In Vitro PPI Assay)

This screening assay measured compound activity in vitro on GATOR2/Sestrin2 complexes purified via immunoprecipitation of stably expressed Flag-WDR24 from HEK293T cells. HEK293T cells (293 Ts) were engineered to stably express N-terminally tagged Flag-WDR24 via transduction by lentivirus. Lentiviruses were produced by co-transfection of the lentiviral transfer vector pLJM60 with the ΔVPR envelope and CMV VSV-G packaging plasmids into HEK-293T cells using the XTremeGene 9 transfection reagent. The media was changed 24 hours post-transfection to Dulbecco's Modified Eagle's media (DMEM) supplemented with 30% Inactivated Fetal Serum The virus-containing supernatants were collected 48 and 72 hours after transfection and passed through a 0.45 μm filter to eliminate cells. Target cells in 6-well tissue culture plates were infected in media containing 8 μg/mL polybrene and spin infections were performed by centrifugation at 2,200 rpm for 1 hour. 24 hours after infection, the virus was removed and the cells selected with the appropriate antibiotic. Cells are then grown in DMEM supplemented with 10% fetal bovine serum and antibiotics.

To screen for leucine mimetic compounds, 2,000,000 Flag-WDR24 expressing 293 Ts are plated in a 10 cm tissue culture plate. 72 hours later, cells were placed in standard RPMI media formulated with no amino acids and supplemented with 5 mM Glucose (−AA RPMI, USBiological Life Sciences) for 1 hour then subsequently lysed in lysis buffer (40 mM HEPES, 1% Triton, 10 mM Sodium Beta-Glycerophosphate, 10 mM Sodium Pyrophosphate, 2.5 mM MgCl₂ and protease inhibitors). The Flag-WDR24/endogenous-Sestrin2 complex was isolated as follows: crude lysate (equivalent to 2-4 mg of total protein) in a volume of 1 ml was subjected to immunoprecipitation (IP) with 30 μl of anti-flag resin (SIGMA) for 2 hours at 4° C., washed twice in cold lysis buffer plus 0.5M NaCl and resuspended in 1 ml of cold cytosolic buffer (40 mM HEPES pH 7.4, 140 mM KCl, 10 mM NaCl, 2.5 mM MgCl2, 0.1% TritonX-100). Compounds were then added to each sample at a given concentration of 25 μM and incubated with rotation at 4° C. for 30 minutes. After the incubation period, samples were centrifuged to pellet the Flag-WDR24/endogenous-Sestrin2 complex bound to the anti-flag resin, the supernatant was completely removed and resin was resuspended in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) sample buffer and boiled for 5 minutes. Samples were then processed by SDS-PAGE and western blots are performed with anti-Flag (SIGMA) and anti-Sestrin2 (Cell Signaling Technology) antibodies as described in L. Chantranupong, et al., Cell Reports 9:1-8 (2014).

The resulting western blots were scanned and band intensities corresponding to Sestrin2 and Flag-WDR24 were quantified using the LI-COR® imaging platform. To determine amount of Sestrin2 bound to GATOR2 for each condition, the band intensity for Sestrin2 was normalized to the band intensity of Flag-WDR24. For every batch of compounds tested, a negative control (water) and a positive control (leucine, 25 μM, SIGMA)) were also performed. The depletion of bound endogenous Sestrin2 to Flag-WDR24 by leucine is normalized to represent 100% activity. Compounds are assayed in duplicate and activity of each compound is quantified as percent of leucine activity and averaged. A table listing quantified data from compounds tested is presented in Table 3. Repeated attempts of the assay resulted in a standard deviation of 20% in the average activity of leucine compared to water; therefore, compounds where both duplicates reduce the amount of Sestrin2 bound to GATOR2 by at least 40% at 25 μM were considered statistically significant and were referred to as leucine mimetics. Some compounds increased the amount of Sestrin2 bound to Flag-WDR24 (shown as negative percent activity of leucine in Table 3). Compounds that showed less than −40% of leucine activity were also considered hits and were referred to as leucine antagonists.

Method 2 (Cell-Based mTORC1 Activation)

To demonstrate efficacy of compounds identified as leucine mimetics in intact cells, mTORC1 signaling in response to compound treatment post leucine starvation was measured via western blotting. Upon leucine starvation, addition of exogenous leucine activates mTORC1 when signaling is measured 10 to 90 minutes after addition of leucine, as described in Wang, S., Tsun, Z., et al. Science 347(6218): 188-194 (2015). Therefore, a similar assay was designed to test whether compounds identified as leucine mimetics activate mTORC1 in a similar manner. Briefly, 800,000 HEK293T cells were plated in each well of a 6-well plate in DMEM supplemented with 10% fetal bovine serum and antibiotics. The next day, cells were placed in modified DMEM without leucine (Thermo Scientific) or serum for 1 hour followed by addition of leucine mimetic (n=3) at a given concentration for some period of time greater than 10 minutes. Cells were then lysed, processed for SDS-PAGE and western blotting was performed with antibodies directed against the mTORC1 substrates phosphorylated S6 Kinase (Thr389) and phosphorylated 4EBP1 (Thr37/46) (Cell Signaling Technology) and loading controls (beta-actin, Santa Cruz Biotechnology) as described in Kang, S. A., et al. Science 341(6144): 364-374 (2013). The intensity of the bands corresponding to the phosphorylated substrates were then normalized to the actin band using the LI-COR® imaging platform. Compounds that significantly increased mTORC1 signaling relative to leucine-starved cells treated with no compound (student t-test, p<0.05) were considered active in cells. As a positive control, leucine was added at 100 μM to leucine-starved cells for 60 minutes.

Method 3 (Cell-Based mTORC1 Activation)

To demonstrate efficacy of compounds identified as leucine antagonists or to determine whether weak leucine mimetics enhance the activity of leucine in intact cells, the same paradigm as above was repeated but with the following changes: cells were placed in leucine minus DMEM media (as described in Method 3) for 60 minutes followed by compound (n=3) for some period of time greater than or equal to 60 minutes. After compound treatment, the cells were stimulated with 30 and 100 μM of leucine for 60 minutes. mTORC1 signaling was measured via western blotting as described in Method 2. Compounds that reduced levels of actin-normalized phosphorylated substrates of mTORC1 in response to leucine at either 30 μM or 100 μM in a statistically significant manner (student t-test, p<0.05) were considered active in cells. Compounds that increased levels of actin-normalized phosphorylated substrates of mTORC1 in response to leucine at either 30 μM or 100 μM in a statistically significant manner (student t-test, p<0.05) were considered leucine enhancers in cells. As a control, leucine-starved cells were pre-treated with water prior to addition of leucine. Alternatively, potential leucine antagonists were assayed in HEK293T cells in the same manner described above but without leucine starvation and stimulation. Western blots were performed to determine whether baseline mTORC1 signaling was attenuated upon compound treatment under replete culturing conditions.

Method 4

The ability of compounds to modulate the interaction between Sestrin2 and GATOR2 in cells were measured by repeating the assay described in Methods 2 and 3 but in HEK293T cells engineered to stably express Flag-WDR24 plated in 10 cm tissue culture dishes. The interaction between endogenous Sestrin 2 and Flag-WDR24 was measured from lysate obtained from cells after compound treatment (n=3) as described in Method 1. Briefly, to measure the amount of endogenous Sestrin2 bound to Flag-WDR24 after cell treatment, an immunoprecipitation was performed with the anti-flag resin and the resulting samples were processed for SDS-PAGE and western blotting to measure amounts of endogenous Sestrin 2 bound to Flag-WDR24. Compounds that modulated the amount of Sestrin2 bound to GATOR2 in a statistically significant manner (student t-test, p<0.05) were considered hits.

Method 5 (ALPHALisa Cell-Based Assay)

To demonstrate efficacy of compounds identified as leucine mimetics in intact cells in a plate-based format, mTORC1 signaling in response to compound treatment post leucine starvation was measured via AlphaLISA. Briefly, 1,000,000 HEK293T cells were plated in T-75 cell culture flasks in DMEM supplemented with 10% fetal bovine serum. After cells reached confluency, they were placed in modified DMEM without leucine (Thermo Scientific) with 10% dialyzed fetal bovine serum for 1 hour. Cells were then trypsinized, and replated in 96-well black clear bottom plates at 50,000 cells/well in DMEM without leucine with 10% dialyzed fetal bovine serum. Cells were allowed to adhere to the plate for 2 hours, followed by addition of compounds (n=4) at a given concentration for some period of time greater than 1 hour. After time point is reached, cells were lysed and assayed by p-p70 S6K (Thr389) SureFire Ultra AlphaLISA kit according to manufacturer's instructions (http://www.perkinelmer.com/CMSResources/Images/44-176283MAN_SureFire_TGR70S_p70_pT389.pdf ). Compounds that significantly increased mTORC1 signaling relative to leucine-starved cells treated with no compound (student t-test, p<0.05) were considered mTORC1 activators. Compounds that significantly decreased mTORC1 signaling relative to leucine-starved cells treated with no compound (student t-test, p<0.05) were considered inhibitors in cells. As a positive control, leucine was added at 100 uM to leucine-starved cells for the period of time equal to compound treatment.

Method 6. Thermalshift Protocol (Tm Shift):

Full-length, codon-optimized human Sestrin2 was N-terminally fused with His-MBP tag and cloned into the pMAL6H-C5XT bacterial expression vector. This vector was transformed into Escherichia coli LOBSTR (DE3) cells (Kerafast). Cells were grown at 37° C. to 0.6 OD, then protein production was induced with 0.2 mM IPTG at 18° C. for 12-14 h. Cells were collected by centrifugation at 6,000 g, resuspended in lysis buffer (50 mM potassiumphosphate, pH 8.0, 500 mMNaCl, 30 mM imidazole, 1 mM DTT, 10 μg/ml Benzonase and 1 mM PMSF) and lysed by sonication. The lysate was cleared by centrifugation at 10,000 g for 20 min. Sestrin2 protein was isolated from the soluble fraction to near 100% purity through affinity capture of the His tag followed by ion exchange and size exclusion chromatography. For the thermal shift assay, Sestrin2 protein was diluted to 2 mg/ml in dilution buffer (10 mM Tris HCl pH 7.4, 150 mMNaCl, 1 mM DTT, 0.1 mMEDTA). Prior to performing the thermal shift assay, 2 μl of Sestrin2 protein was combined with 8 μl ROX dye (Thermo Fisher), 1 μL vehicle or compound, and 14 μL dilution buffer per well of a 96-wellplate, and incubated on ice for 1 hour to allow for compound binding. The thermal shift assay was then run on an Agilent MX3005p and each compound was assayed in triplicate at 10 μM, 100 μM and 1000 μM. Incubation with leucine shifted the melting temperature of Sestrin2 by 2.16 to 11.61 degrees Celsius in a dose dependent manner. A positive shift of 2 degrees or more is considered statistically significant based on the CV % variability of repeated thermal shift measurements of Sestrin2 incubated with vehicle.

Method 7. Indirect Ligand Binding Assay (TLBA)

The binding of Sestrin2 to leucine or other ligand was detected either in intact cells, in vitro or with purified protein through immune-detection with the rabbit monoclonal anti-Sestrin2 antibody from Cell Signaling Technology (CST, Cat #8487). Binding of the CST antibody to native (non-denatured) Sestrin2 was modulated by the binding of leucine in such a way that the affinity of the antibody decreases upon leucine binding. Similarly, the affinity of the CST antibody for native Sestrin2 decreased upon compounds binding to native in a manner similar as leucine. Conversely, compounds that destabilized Sestrin2 as measured by thermal shift assay increased the affinity of the CST antibody for non-denatured Sestrin2. As a result, multiple formats of this indirect ligand-binding assay (ILBA) were developed that measure the affinity of the CST anti-Sestrin2 antibody after binding of leucine or compound. In one version, the assay was performed with crude lysate generated from a human cell line after a 1-hour period of amino acid starvation (cells are lysed in 1% Triton, 10 mM beta-glycerol phosphate, 10 mM sodium pyrophosphate, 40 mM HEPES [pH 7.4], 150 mM NaCl and 2.5 mM MgCl₂). Lysate was then incubated with leucine or other compound for 1 hour on ice or at room temperature. After compound incubation, samples were subjected to immunoprecipitation with the CST anti-Sestrin2 antibody for 1.5 hours followed by a 30-minute incubation with protein-A sepharose as described in L. Chantranupong, et al., Cell Reports 9:1-8 (2014). The sepharose conjugated antibody-protein complex was precipitated via centrifugation and the flow-through was subjected to a second round of immunoprecipitation with a rabbit polyclonal anti-Sestrin2 antibody (Protein Tech, #10795-1-AP) to determine that total Sestrin2 protein levels between samples were equal. SDS-PAGE was performed with the immunoprecipitation samples followed by western-blot with the mouse monoclonal anti-Sestrin2 antibody from SIGMA (cat #WH0083667M3). Leucine binding induced a significant decrease in the intensity of the band corresponding to Sestrin2 by 50% or more on the immunoblot with samples immunoprecipitated with the anti-Sestrin2 antibody from CST but led to no change in the Sestrin2 band on the immunoblot with samples immunoprecipitated with the Protein Tech antibody. This version of the assay also measured increased instability of Sestrin2 induced by incubation with compounds. The assay was performed in the same manner, but compounds that destabilized Sestrin2 (as measured by thermal shift assay) resulted in an increase in immunoblot band intensity corresponding to Sestrin2 immunoprecipitated using the CST antibody.

This assay was also performed in cultured human cells over-expressing Sestrin2 N-terminally fused to a Flag tag. In this version of the assay, the procedure remained the same, but immunoblotting was performed with a mouse anti-Flag antibody (#F3165, SIGMA). The decrease in affinity of the CST antibody upon leucine or γ-methylleucine binding was not observed when an ILBA was performed with a point mutant form of Sestrin2 unable to bind leucine.

In another version of the assay, cultured human cells were subjected to some combination of amino acid starvation for 1-hour followed by stimulation with leucine or compounds. One hour after stimulation, cells were lysed and processed as described above with the exception of the 1-hour ligand-binding step.

The indirect ligand-binding assay was also performed in a multi-well format using ALPHAlisa technology (Perkin Elmer). This version of the assay required biotinylated anti-Sestrin2 antibody, Streptavidin donor beads (Perkin Elmer) coupled with either anti-Flag acceptor beads (Perkin Elmer) for detection of overexpressed Flag-Sestrin2, or coupled with mouse anti-Sestrin2 antibody (SIGMA) and anti-mouse acceptor beads (Perkin Elmer) for detection of endogenous Sestrin2.

The assay was performed as described above, but with the following modifications: for the leucine or compound binding portion of the assay, crude lysate generated from cells transiently or stably overexpressing human Flag-Sestrin2 after 1 hour of amino acid starvation was diluted to 0.8 mg/ml of total protein in lysis buffer and arrayed in a multi-well plate such as a 96-well plate. For detection of endogenous Sestrin2, crude lysate was diluted to 4 mg/ml of total protein in lysis buffer. Leucine or compound was added to each well and the plate was incubated on ice or at room temperature for 1 hour with gentle agitation. During the ligand-binding step, biotinylated anti-Sestrin2 antibody (CST) was diluted to 5 nM in ALPHAlisa immunoassay buffer (Perkin Elmer), and 5 nM of mouse anti-Sestrin2 antibody (SIGMA was combined with a 4× stock of the anti-mouse acceptor bead (40 μg/ml) for assays detecting endogenous Sestrin2. For detection of Flag-Sestrin2, a 4× stock of anti-Flag acceptor beads (40 μg/ml) in immunoassay buffer was prepared. After the ligand-binding step, 5 μL of lysate was combined with 10 μL of the biotinylated anti-Sestrin2 antibody, 12.5 μL of the mouse Sestrin2 antibody/anti-mouse acceptor bead mix or anti-Flag acceptor beads, and 10 μL of ALPHAlisa immunoassay buffer and was incubated at room temperature for 1 hour. Finally, 12.5 μL of streptavidin donor beads (160 μg/ml in immunoassay buffer) were added for an additional hour in the dark prior to reading the plate on an Envision plate reader.

The ALPHAlisa assay was also performed as described but with purified Sestrin2 protein at a final reaction concentration of 3 ng/ml diluted in immunoassay buffer.

Finally, the ALPHAlisa was performed with lysate from cells treated with leucine or compound under amino acid starved conditions prior to lysing. Cell-based treatment was performed in a multi-well plate, and 15 μL of lysate (1 mg/ml total protein) was used per ALPHAlisa reaction in combination with 10 μL of biotinylated antibody, 12.5 μL of the antibody/acceptor bead mix and 12.5 μL of the streptavidin donor bead mix.

The indirect ligand-binding assay was also performed with a capture-based method such as a sandwich ELISA as performed in the art. In one version of the assay, the ILBA was performed using the MULTI-ARRAY® technology developed by Meso-Scale Discovery (MSD). The MSD system was based on electrochemiluminescence detection of antibody binding to analyte. The ILBA was performed with crude lysate expressing endogenous Sestrin2 or overexpressed Flag-Sestrin2 and leucine treatment was performed either in vitro or in cells prior to lysis. For the in vitro ILBA with endogenous Sestrin2, crude lysate (0.8 mg/ml total protein) was prepared and leucine binding was performed in the same manner described for the ALPHAlisa ILBA. After ligand binding was complete, biotinylated anti-Sestrin2 antibody from CST was added to each well to a final concentration of 0.25 μg/ml and was incubated with gentle agitation for 1 hour at 4° C. Capture of each sample into a well of a 96-well plate was accomplished in one of the following ways: streptavidin-coated MSD plates or bare MSD plates coated with mouse anti-Sestrin2 antibody from SIGMA. Capture required 25 μL of sample per well followed by 1-hour incubation with shaking at 350 rpm. After sample capture, wells were washed three times with Tris buffered saline with 0.1% Tween (TBS-T). If the samples were captured onto the streptavidin-coated plate, mouse monoclonal anti-Sestrin2 antibody (SIGMA) was then added to a final concentration of 1 μg/ml for 1 hour with shaking at 350 rpm. Wells were washed again in TBS-T, and anti-mouse secondary SULFO-TAG antibody at a final concentration of 1 μg/ml (MSD) was added for an hour with shaking at 350 rpm. Finally, wells were washed three times with TBS-T and 2× Read Buffer (MSD) was added and the plate was read immediately on a MSD instrument. If samples were captured with bare plates coated with the mouse anti-Sestrin2 antibody, after washing, a streptavidin secondary SULFO-TAG antibody (MSD) was added at a final concentration of 1 μg/ml for 1 hour with shaking followed by washes and incubation with Read Buffer prior to analysis.

In another version of this assay, crude lysate overexpressing Flag-Sestrin2 was analyzed and captured or detected with the mouse monoclonal anti-Flag antibody (SIGMA) using the same MSD-based protocol as described above.

For all assays, compounds that decreased the signal corresponding to immunoreactivity of Sestrin2 in a significant manner were considered leucine mimetics while compounds that increased the signal in a significant manner were considered potential leucine antagonists

Table 3 shows the activity of selected compounds of this invention. The compound numbers correspond to the compound numbers in Tables 1 and 2. Compounds having an activity designated as “A” provided a % activity relative to leucine of ≥40%, compounds having an activity designated as “B” provided a % activity relative to leucine of ≤−40%; compounds having an activity designated as “C” provided a % activity relative to leucine of between -40 and 40%. Compounds having an activity designated as “D” provided a shift relative to DMSO control of 0.5 to 2 fold, compounds having an activity designated as “E” provided a shift relative to DMSO of 2.1-5 fold, compounds having an activity designated as “F” provided a shift relative to DMSO of 5.1-10 fold and compounds having an activity designated as “G” provided a shift relative to DMSO of 10.1 to 14 fold, at the designated concentrations.

Activity for the % activity relative to leucine assay was determined using assay Method 1. Activity for the cell-based mTORC1 activation assay was determined using assay Method 2.

TABLE 3 Assay Data for Exemplary Compounds Activity of Cell-Based Cell-Based mTORC1 Compound Leucine: mTORC1 Activation Number % Activity Activation Concentration (μM) I-1 B I-2 B I-3 B I-4 C I-5 B I-6 C I-7 B I-8 B I-9 C E 100 I-10 C D 30 and 100 I-11 C I-12 C I-13 C I-14 B I-15 C I-16 C I-17 C I-18 C I-19 C I-20 C I-21 C I-22 C I-23 C D to F 100 I-24 A I-25 C I-26 C I-27 A I-28 C I-29 A I-30 A I-31 A I-32 A I-33 C I-34 C I-35 A I-36 B I-37 A E to F 100 I-38 C I-39 C I-40 A I-41 A I-42 A D to F 100 I-43 A D to E 100 I-44 A D 100 I-45 B I-46 C D 100 I-47 C D 100 I-48 C I-49 C I-50 C I-145 A I-146 A I-147 A I-148 A I-149 C I-150 C I-151 C I-152 C I-153 C I-154 C I-155 C I-156 C I-157 B to C I-158 C I-159 A I-160 C I-161 C I-162 C I-163 A I-164 A I-165 A to C I-166 C I-167 A D to F 100 I-168 D to E 100

Table 4 shows selected compounds of this invention active in the ALPHALisa cell-based assay (Method 5). The compound numbers correspond to the compound numbers in Tables 1 and 2. Compounds listed in Table 4 are mTORC1 activators and have an activity of >2-fold versus the positive leucine control.

TABLE 4 Exemplary Compounds Active in the ALPHALisa Cell-based Assay Compound Number I-44 I-43 I-42 I-167 I-253 I-145 I-252 I-251 I-250 I-88 I-56 I-96 I-206 I-122 I-90 I-128 I-195 I-194 I-193 I-93 I-249 I-120 I-190 I-189 I-248 I-247 I-246 I-185 I-183 I-179 I-178 I-177 I-176 I-175 I-207 I-245 I-210 I-244 I-243 I-241 I-240 I-239 I-238 I-237 I-236 I-235 I-234 I-233 I-232 I-231 I-230 I-229 I-228

Table 5 shows selected compounds of this invention active in the Thermalshift assay (Method 6). The compound numbers correspond to the compound numbers in Tables 1 and 2. Compounds listed in Table 5 exhibited a positive shift of 2 degrees or more.

TABLE 5 Exemplary Compounds Active in the Thermalshift Assay Compound Number I-44 I-43 I-42 I-31 I-27 I-4 I-47 I-167 I-164 I-163 I-254 I-253 I-145 I-252 I-251 I-250 I-206 I-122 I-203 I-90 I-201 I-129 I-128 I-196 I-195 I-194 I-93 I-120 I-191 I-179 I-178 I-177 I-176 I-175 I-209 I-208 I-207 I-245 I-210 I-244 I-237 I-235 I-233 I-232 I-231 I-229

General Materials and Methods for In Vivo Tests

Animal Use: Male Sprague Dawley rats weighing 175-200 g (Charles River Laboratories, Wilmington, Mass.) were group-housed upon arrival (Yale University, New Haven Conn.) and acclimated 5 days before initiating experimental studies. Rats were provided food and water ad libitum except during protocol-specified fasting. The animals were monitored daily for clinical signs. A qualified veterinarian provided oversight for all rodent procedures. All personnel received training from Yale animal care and use committee (IACUC). All animal procedures were conducted at Yale University in strict accordance with the National Institutes of Health IACUC and were approved by the Yale Animal Care and Use Committee.

Behavioral Analysis Using the Female Urine Sniffing Test (FUST): The FUST was conducted according to published procedures (Malkesman, O. et al, Biol Psychiatry 67(9): 864-71 (2010)), 24 hr post-dosing. Briefly, rats were habituated for 60 min to a cotton swab dipped in tap water in their home cage. Next, rats were exposed to a 2nd cotton swab dipped in tap water and 45 min later they were exposed to a 3rd cotton swab infused with fresh rat urine from 11 to 14-week-old female rats in estrus. The total time (s) spent sniffing the cotton-tipped applicator was quantitated over 5 min for each animal.

Behavioral Analysis Using the Locomotor Activity Assessment (LMA): LMA was assessed according to published procedures (Warner-Schmidt, J. L. & and Duman, R. S. PNAS 104(11): 4647-52 (2007)), in an open field fitted with automated activity meters consisting of parallel rows of infrared beams. The number of beam-breaks were recorded over a 30 min interval for each animal.

Behavioral Analysis Using the Novelty Suppressed Feeding Test (NSFT): The NSFT was conducted as previously described (Warner-Schmidt, J. L. & Duman, R. S. PNAS 104(11): 4647-52 (2007)). Rats were fasted in their home cages for 20 hr and then placed in a Plexiglas open field (76.5 cm×76.5 cm×40 cm) with a small amount of food in the center. Animals were allowed to explore the open field for 8 min and the latency to feed (s) was recorded.

Behavioral Analysis Using the Sucrose Preference Test (SPT): Rats were habituated to a palatable sucrose 1% sucrose solution for 48 hrs to avoid neophobia. Rats were treated with NV-5138 or Veh at the end of day 0 and the SPT was performed 24 hrs post-administration on day 1. For the SPT, rats were deprived of water for 6 hrs and exposed for 60 min to two bottles with equal volumes of 1% sucrose or water. The ratio of the volume of sucrose water consumed to total water consumed during the 1 hr test was defined as sucrose preference (e.g., a ratio of 1 would indicate the rat consumed only 1% sucrose, while a ratio of 0.5 would indicate that the rat drank equal amounts of 1% sucrose and water).

Chronic Unpredictable Stress (CUS) Conditions: Rats were exposed to a variable sequence of 12 unpredictable stressors, preventing habituation as described (Li, N. et al., Biol Psychiatry 69(8): 754-61 (2011)). The following twelve stressors were applied (2 per day, for 25 days): cage rotation, light on, light off, cold stress, isolation, swim stress, food and water deprivation, wet bedding, stroboscope, cage tilt, odor exposure and group housing. The animals in non-stressed (NS) groups were housed normally without the application of external stressors. Both NS and CUS rats were handled and weighed weekly.

Marmoset Human Threat Test (HTT): Marmosets were challenged by the presence of a human observer over a long period of time on a regular basis. Such chronic stimulation is known to increase plasma cortisol and the subsequent increase in hypothalamic-pituitary-adrenal function contributed to the pathophysiology of depressive illness.

Example A: Behavioral Changes in the Novelty Suppressed Feeding and Femal Urine Sniffing Tests After A Single Dose of Compound or Ketamine

Study Design. Thirty-two (32) male Sprague Dawley Male rats weighing between 175 and 200 g were randomized into 4 study groups (n=8/treatment group), following a 5-day acclimation period. On study day 0, rats received a single dose of either saline (Sal) or ketamine (Ket) in Groups 1 and 2, respectively, by intraperitoneal injection (i.p.). The rats in Group 3 and 4 received a single dose of the NV-5138 vehicle (Veh, 0.5% Methylcellulose/0.1% Tween-80) or NV-5138 (160 mg/kg), respectively, by oral gavage. All rats were subjected to the FUST on day 1, 24 hrs after dosing. On day 2, 48 hrs after dosing, the LMA of all rats was measured in an open field. Rats were then fasted for 20 hrs and subjected to the NSFT, 72 hrs post-dose. The study design is presented in Table 6. The timeline of the test article administration and the 3 behavioral tests is summarized in FIG. 1.

Preparation of Test Articles. Ket (Sigma, cat #K1884) was dissolved in Sal at a concentration of 10 mg/mL. A volume of 1 ml/kg of Sal or Ket was injected i.p. for Groups 1 and 2, respectively. NV-5138 (Navitor, lot #06) was prepared by dissolving in Veh (0.5% methylcellulose/0.1% Tween-80) at a concentration of 50 mg/mL. The dosing volume based on the weight of the animal (3.2 mL/kg) of Veh or NV-5138 was administered by oral gavage to study animals in Groups 3 and 4, respectively. Test articles were prepared the day of dosing.

Results. Results for the day one FUST are summarized in FIG. 2. Treatment with Ket significantly increased the amount of time that male rats spent sniffing female urine by 2.1-fold (36.5±7.9 s compared to 17.4±3.9 s in the Ket Group 2 vs. Sal Group 1, respectively, p<0.05). Similarly, treatment with NV-5138 significantly increased the amount of time male rats spent sniffing female urine by 2.9-fold (33.8±2.9 s compared to 11.6±6.2 s in the in the NV-5138 Group 4 compared to the Veh Group 3, respectively, p<0.01). Results for the day 2 LMA are summarized in FIG. 3. The mean number of beam breaks were quantitated. There were no significant differences in LMA between groups using an unpaired 2-tailed students t-test. Results for the day 3 NSFT are summarized in FIG. 4. A significant 31% decrease in the latency to feed (p<0.01) was observed in Group 2 (Ket) compared with Group 1 (Sal). Similarly, a significant 36% decrease (p<0.01) in the latency to feed was observed in Group 4 (NV) compared with Group 3 (Veh).

TABLE 6 Study Design Example A Weight Behavioral Group n sex (g) Route Treatment Tests Group 1 8 M 175-200 i.p. Sal FUST, Group 2 8 M 175-200 i.p. Ket (10 mg/kg) LMA & Group 3 8 M 175-200 Oral Veh NSFT Group 4 8 M 175-200 Oral NV-5138 (160 mg/kg)

Example B: Comparative Effects of Single Dose of NV-5138 and Ketamine Administration of the mTORC1 Signaling Pathway and Synaptic Protein Expression in Synaptosome Preparations Derived from the Rat Pre-Frontal Cortex

Study Design. Forty-eight (48) male Sprague Dawley rats weighing between 175 and 200 g were randomized into 8 study groups (n=6/group), following a 5-day acclimation period. On study day 0, rats in Groups 3 and 7 received a single dose of Sal while Groups 4 and 8 received a single dose of Ket (10 mg/kg) each by i.p. injection. The rats in Groups 1 and 5 received a single dose of Veh while Groups 2 and 6 received a single dose of NV-5138 (160 mg/kg) each by oral gavage. One hour after dosing, rats in Groups 1-4 were sacrificed by conscious decapitation and followed by collection of the PFC. Crude synaptosomes were prepared from the PFC and three mTORC1 substrates, pmTOR, pp70S6K and p4E-BP1, and corresponding total protein loading controls (mTOR, p70S6K, and GAPDH) were quantitated by WB. Twenty-four hours after dosing, rats in Groups 5-8 were sacrificed by conscious decapitation and collection of the PFC. Crude synaptosomes were prepared from the PFC and the synaptic proteins (GluR1 and PSD95), as well as the total protein loading control (GAPDH), were quantitated by WB. The study design is presented in Table 7. The timeline of the test article administration and sacrifice of rats for WB is provided in FIG. 5.

Formulation of Ket and NV-5138 for Administration. Ket (Sigma, cat #K1884) was dissolved in Sal at a concentration of 10 mg/mL. A volume of 1 mL/kg was injected i.p. NV-5138 (Navitor, Lot #06) was prepared by dissolving in Veh at a concentration of 50 mg/mL. The dosing volume based on the weight of the animal (3.2 mL/kg) was administered by oral gavage. Test articles were prepared the day of dosing.

Prefrontal Cortex Synaptosome Preparations. The brain was dissected from rats in all groups (n=6/group) and rinsed in PBS. The PFC was collected as shown in FIG. 6 and homogenized at 4° C. in homogenization buffer (0.32 M sucrose, 20 mM HEPES at pH 7.4, 1 mM EDTA, 5 mM NaF, 1 mM NaVO₃ and protease inhibitor cocktail (Roche; Ser. No. 19/543,200)). The homogenate was centrifuged for 10 min at 2,800 rpm at 4° C. after which the supernatant was removed and re-centrifuged at 12,000 rpm for 10 min at 4° C. The resulting pellet containing crude synaptosomes was re-suspended in Lysis buffer (50 mM Tris-HCl (pH 7.5), 150 mM NaCl, 1% Triton X-100, 0.1% SDS, 2 mM, EDTA, 1 mM NaVO₃, 5 mM NaF and protease inhibitor cocktail) and sonicated on ice for 20 s at 50% amplitude. The protein concentration was determined by Bradford assay and all samples were mixed with loading buffer (60 mM Tris-HCl pH 6.8, 20 mM DTT, 2% SDS, 10% glycerol, 5% β-mercaptoethanol and 0.01% Bromophenol blue) and stored at -20° C. until WB analysis.

Western Blot Analysis: Western blot analysis for GluR1, PSD95 and GAPDH was performed as previously described. Briefly, synaptosomes preparations (15 μg total protein) were loaded into 10-15% SDS PAGE gel for electrophoresis and transferred to a polyvinylidene difluoride (PVDF) membrane in transfer buffer (10× premixed electrophoresis buffer contains 25 mM Tris, 192 mM glycine, pH 8.3; Bio-Rad). The PVDF membranes were blocked for 1 hr at room temperature with blocking buffer (2% BSA in PBS-T (10 mM Phosphate, pH 7.4, 2.7 mM KCl, 137 mM NaCl and 0.1% Tween-20)) and subsequently incubated with primary antibodies: rabbit anti-pmTOR at 1:1000 (Cell Signaling; #5536), rabbit anti-mTOR at 1:1000 (Cell Signaling; #2972), rabbit anti-pp70S6K at 1:1000 (Cell Signaling; #9205), rabbit anti-p70S6K at 1:1000 (Cell Signaling; #2708), rabbit anti-p4E-BP1 at 1:1000 (Cell Signaling; #2855), rabbit anti-GluR1 at 1:1000 (Cell Signaling; #13185), rabbit anti-Synapsin 1 at 1:1000 (Cell Signaling; #5297), rabbit anti-PSD95 at 1:1000 (Cell Signaling; #9644) and rabbit anti-GAPDH at 1:1000 (Cell Signaling; #5174) in blocking buffer overnight at 4° C. The next day, membranes were washed 3 times in PBS-T buffer and incubated with horseradish peroxidase conjugated anti-mouse or anti-rabbit secondary antibody at 1:5000 to 1:10000 (Vector Laboratories Inc) for 1 hr. After final three washes with PBS-T buffer, bands were detected using enhanced chemiluminescence. The blots then were incubated in the stripping buffer (2% SDS, 100 mM β-mercaptoethanol, 50 mM Tris-HCl pH 6.8) for 30 min at 50-55° C. followed by three washes with PBS-T buffer. The stripped blots were kept in blocking solution for 1 hr and incubated with the primary antibody directed against total levels of the respective protein or GAPDH for loading control. Densitometric analysis of phospho- and total immunoreactivity for each protein was conducted using NIH Image J software. The resulting densitometric readings were used to generate a ratio of phopho-protein to their respective total protein levels or GAPDH as indicated. The resulting ratio was further normalized to Sal or Veh treated control group for each protein.

Results. Results for the WB analysis of pmTOR, pp70S6K and P4E-BP, normalized to control Veh or Sal, is summarized in FIG. 7. NV-5138 and Ket administration significantly increased the levels of pmTOR and p4E-BP1 in crude synaptosomes prepared from the PFC 1 hr after administration. Furthermore, NV-5138, but not Ket, significantly increased levels of pp70S6K 1 hr after administration. Results for WB analysis of synaptic proteins GluR1 and Synapsin 1 are summarized in FIG. 8. NV-5138 and Ket administration significantly increased the levels of GluR1 and Synapsin 1 in crude synaptosomes prepared from the PFC 24 hr after administration. Furthermore, Ket significantly increased levels of PSD95 24 hr after administration while there was a trend toward increased expression following NV-5138 administration.

TABLE 7 Study Design Example B WB Weight Time- antibodies Group n Sex (g) point Route Treatment used Group 1 6 M 175-200  1 hour Oral Veh pmTOR, Group 2 6 M 175-200  1 hour Oral NV-5138 mTOR, (160 mg/kg) pp70S6K, Group 3 6 M 175-200  1 hour i.p. Sal p70S6K, Group 4 6 M 175-200  1 hour i.p. Ket (10 mg/kg) p4E-BP1, & GApDH Group 5 6 M 175-200 24 hours Oral Veh GluR1, Group 6 6 M 175-200 24 hours Oral NV-5138 Synapsin 1 (160 mg/kg) PSD95, & Group 7 6 M 175-200 24 hours i.p. Sal GAPDH Group 8 6 M 175-200 24 hours i.p. Ket (10 mg/kg)

Example C: Effect of Single Roal Dose of NV-5138 on mTORC1 Signaling Pathway in Multiple Regions of the Rat Brain

Study Design: Ten (10) male rats weighing between 175 and 200 g were randomized into 2 study groups (n=5/group), following a 5-day acclimation period. Group 1 received a single administration of Veh by oral gavage and group 2 received a single administration of NV-5138 (160 mg/kg prepared in Veh) by oral gavage. One hour following administration, rats were sacrificed by conscious decapitation, plasma was collected for analysis of NV-5138 exposure in addition to the isolation of the PFC, hippocampus, striatum, neocortex and cerebellum by microdissection. Total protein extracts were prepared from the harvested tissues and submitted to WB analysis followed by quantitative analysis of selected mTORC1 substrates. The study design is presented in Table 8. The timeline of the test article administration, and sacrifice of rats for WB is provided in FIG. 9.

Formulation of NV-5138 (160 mg/ml): NV-5138 (Navitor, Lot #09) was prepared by dissolving in Veh at a concentration of 160 mg/mL. The dosing volume based on the weight of the animal (10 mL/kg) was administered by oral gavage to study animals in Group 2. Test articles were prepared the day of dosing.

Western Blot Analysis: Synaptosomes preparations (15 μg of total protein) were loaded and separated on NuPAGE 4-12% Bis-Tris gels and transferred to PVDF membrane (Immobilon-FL PVDF membrane, Millipore) using CAPS Buffer (10 mM 3-(Cyclohexylamino)-1-propanesulfonic acid, 12.5% Ethanol pH=10). After transfer, membranes were incubated for 1 hr at room temperature in Odyssey blocking buffer (Licor). After blocking, membranes were incubated at 4° C. overnight with primary antibodies. Primary antibodies used were rabbit anti-^(S400/440)pS6 (cell signaling; #5364) at 1:1000 and mouse anti-a-tubulin (Sigma; #T5168) at 1:10000 in Odyssey blocking buffer. The next day, membranes were washed three times in IX TBS-Tween (25 mM Tris, pH 7.4, 3.0 mM KCl, 140 mM NaCl and 0.05% Tween-20) and incubated with dye-coupled secondary antibodies (goat anti-mouse IRdye680, and goat anti-rabbit IRdye800 from LI-COR) at 1:20000 in Odyssey blocking buffer for 30 min then wash three times in IX TBS-Tween. Signals were quantified using the Odyssey Infrared Imaging System (LI-COR Bioscience). The resulting densitometric readings were used to generate a ratio of phopho-protein to α-tubulin. The resulting ratio was further normalized to vehicle treated control group.

Prefrontal Cortex Synaptosome Preparations: One hour following dosing rats were sacrificed by conscious decapitation, plasma and brain were collected. Brains were dissected for each group (n=5, Veh; n=5, NV) and rinsed in PBS. PFC, striatum, hippocampus, neocortex and cerebellum were collected as shown in FIG. 10 and homogenized at 4° C. in homogenization buffer (0.32 M sucrose, 20 mM HEPES at pH 7.4, 1 mM EDTA, 5 mM NaF, 1 mM NaVO₃ and protease inhibitor cocktail (Roche; Ser. No. 19/543,200)). Homogenates were centrifuged for 10 min at 2,800 rpm at 4° C. after which supernatants were removed and re-centrifuged at 12,000 rpm for 10 min at 4° C. Resulting pellets were re-suspended in Lysis buffer (50 mM Tris-HCl (pH 7.5), 150 mM NaCl, 1% Triton X-100, 0.1% SDS, 2 mM, EDTA, 1 mM NaVO₃, 5 mM NaF and protease inhibitor cocktail) and sonicated on ice for 20 s at 50% amplitude. Total protein concentrations were determined by Bradford assay and all samples were mixed with loading buffer (50 mM Tris-HCl pH 6.8, 2% SDS, 5% glycerol, 5% P-mercaptoethanol and 0.01% Bromophenol blue) and stored at -20° C. until WB analysis.

Compound Analysis. For determination of compound levels in plasma, proteins were precipitated from 50 μL of the resulting tissue homogenate containing 150 μL of the internal standard (tolbutamide) in acetonitrile followed by centrifugation at 3000 rpm for 10 min. One hundred microliters of the resulting supernatant were added to 100 μL of water, mixed well and injected on the LC-MS/MS system using the following program for assessing compound levels:

Phenomenex LEIX Cellulose column (4.6×150 mm, 5 μm)

Mobile Phase A—0.1% Formic Acid in Water

Mobile Phase B—0.1% Formic Acid in Acetonitrile

Gradient:

Initial—40% A

-   -   2 minutes—40% A     -   2.1 minutes—2% A     -   3 minutes—2% A     -   3.1 minutes—40% A     -   4 minutes—40% A

Flow rate 0.8 mL/min

Column Temp 40 degrees C.

Sciex 5500 Triple Quad Mass Spec

Results. Results for brain region exposure to NV-5138 are summarized in FIG. 11. In summary, the oral administration of NV-5138 at 160 mg/kg in rats having ad libitum access to food resulted in significant activation of mTORC1 in most, but not all of the major regions of the brain.

TABLE 8 Study Design for Example C WB Weight Tissues antibodies Group n sex (g) Route Treatment harvested used Group 1 5 M 175-200 Oral Veh Plasma, PFC, pS6 & Group 2 5 M 175-200 Oral NV-5138 striatum, α-tubulin (160 mg/kg) hippocampus, neocortex and cerebellum

Example D: Effect of Single Oral Dose of NV-5138 or Leucine on mTORC1 Signaling Pathway in Rat Brain and Selected Peripheral Organs

Study Design: Thirty (30) male rats weighing between 175 and 200 g were randomized into 3 study groups (n=10), following a 5-day acclimation period. Test articles were administered by oral gavage as the doses shown in Table 9 and the timeline shown in FIG. 12. One hour following dosing rats were sacrificed by conscious decapitation, plasma, brain and selected peripheral tissues were harvested for compound level and WB analysis. Tissues were prepared for WB to quantitate the mTORC1 substrate pS6 as a measure of mTORC1 activity.

Preparation of Test Articles: NV-5138 (Navitor, Lot #12) and Leucine (Leu, Sigma; #L8912) were prepared by dissolving in Veh (0.5% methylcellulose/0.1% Tween-80) at a concentration of 16 mg/mL and 100 mg/mL, respectively. The dosing volume based on the weight of the animal (10 mL/kg) was administered by oral gavage. Test articles were prepared the day of dosing.

Tissues Preparations: One hour following dosing rats were sacrificed by conscious decapitation, plasma, brain and peripheral tissues were harvested and immediately frozen in liquid nitrogen. Tissues were thawed and homogenized for 1 min twice using MP homogenizer in Lysis Buffer (Cell lysis buffer: 1% Triton X-100, 50 mM HEPES pH 7.4, 100 mM NaCl, 2 mM EDTA, 10 mM Beta-glycerophosphate, 10 mM Sodium pyrophosphate, and 1 protease inhibitor tab per 50 mL fresh) at 4° C. Lysates were then sonicated on ice for 20 s at 50% amplitude. The protein concentration was determined by Bradford assay and all samples were mixed with loading buffer (50 mM Tris-HCl pH 6.8, 2% SDS, 5% glycerol, 5% β-mercaptoethanol and 0.01% Bromophenol blue) and stored at −20° C. until WB analysis.

Western Blot (WB) Analysis. Equal amounts of each sample (15 μg of total protein) were loaded and separated on NuPAGE 4-12% Bis-Tris gels and transferred to PVDF membrane (Immobilon-FL PVDF membrane, Millipore) using CAPS Buffer (10 mM 3-(Cyclohexylamino)-1-propanesulfonic acid, 12.5% Ethanol pH=10). After transfer, membranes were incubated for 1 hr at room temperature in Odyssey blocking buffer (Licor). After blocking, membranes were incubated at 4° C. overnight with primary antibodies. Primary antibodies used were rabbit anti-S400/440pS6 (cell signaling; #5364) at 1:1000, mouse anti-GAPDH (Sigma; #G8795) at 1:1000 and mouse anti-a-tubulin (Sigma; #T5168) at 1:10000 in Odyssey blocking buffer. The next day, membranes were washed three times in 1×TBS-Tween (25 mM Tris, pH 7.4, 3.0 mM KCl, 140 mM NaCl and 0.05% Tween-20) and incubated with dye-coupled secondary antibodies (goat anti-mouse IRdye680, and goat anti-rabbit IRdye800 from LI-COR) at 1:20000 in Odyssey blocking buffer for 30 min then wash three times in IX TBS-Tween. Signals were quantified using the Odyssey Infrared Imaging System (LI-COR Bioscience). The resulting densitometric readings were used to generate a ratio of phopho-protein to a-tubulin or GAPDH. The resulting ratio was further normalized to vehicle treated control group.

Compound Analysis. For determination of compound levels in the tissue preparations, 70% isopropyl alcohol at a ratio of 3:1 v:w (μL:mg) was added to the tissue samples followed by homogenization with a bead beater (Biospec). Proteins were precipitated from 50 μL of the resulting tissue homogenate in 150 μL of acetonitrile containing of the internal standard (tolbutamide) followed by centrifugation at 3000 rpm for 10 min. One hundred microliters of the resulting supernatant was added to 100 μL of water, mixed well and injected on the LC-MS/MS system using the following program for assessing compound levels:

Phenomenex LUX Cellulose column (4.6×150 mm, 5 μm)

Mobile Phase A—0.1% Formic Acid in Water

Mobile Phase B—0.1% Formic Acid in Acetonitrile

Gradient:

-   -   Initial—40% A     -   2 minutes—40% A     -   2.1 minutes—2% A     -   3 minutes—2% A     -   3.1 minutes—40% A     -   4 minutes—40% A

Flow rate 0.8 mL/min

Column Temp 40 degrees C.

Sciex 5500 Triple Quad Mass Spec

Results. The results of a single administration of NV-5138 on activation of mTORC1 is summarized in FIG. 13. NV-5138 resulted in significant activation of mTORC1 as shown by increased pS6 levels in rat brain in contrast to Leu where no activation was observed. In contrast to the brain treatment, Leu and NV-5138 significantly increased the level of pS6 in rat kidney, heart, tibialis anterior, and epididymal fat. A significant increase of pS6 levels in testes and liver occurred after dosing with Leu however, significant activation was only observed in the testes but not the liver following NV-5138 administration.

TABLE 9 Study Design Example D WB Weight Treat- Tissues antibodies Group N sex (g) Route ment harvested used Group 1 10 M 175-200 Oral Veh Plasma, pS6, Group 2 10 M 175-200 Oral Leu brain, α-tubulin (500 heart, lung, tubulin, & mg/kg) liver, GAPDH Group 3 10 M 175-200 Oral NV-5138 gastroc- (160 nemius mg/kg) spleen, kidney, testes, eyes, tibialis anterior, epididymal fat, thymus

Example E: The Effect of a Single Dose of NV-5138 on the Sucrose Preference and Novelty Suppressed Feeding Tests and Synaptic Protein Expression

Study Design: Fifty-six (56) male rats weighing between 175 and 200 g were randomized into 4 study groups (n=14/group), following a 5-day acclimation period. On study day minus 20, two groups of rats were subjected to CUS for 25 days and two groups of rats were housed normally serving as the NS group. On the day 21 of the CUS protocol, rats received a single dose of either Veh or NV-5138 (160 mg/kg) by oral gavage (day 0). The SPT and NSFT were performed 24 and 48 hrs post-administration (days 1 and 2), respectively. Upon completion of the behavioral tests, after 25 days of the CUS protocol a second dose of NV-5138 or Veh was administered on day 5 and rats were sacrificed 24 hrs later by conscious decapitation. Crude synaptosomes were prepared from the PFC and the synaptic proteins, GluR1 and PSD95 were quantitated by WB. The study design is presented in Table 10. The timeline of test article administration, behavioral tests, and sacrifice of rats for WB is provided in FIG. 14.

Formulation of NV-5138 (50 mg/mL): NV-5138 (Navitor, Lot #07) was prepared by dissolving in Veh to a concentration of 50 mg/mL. The solution was administered to rats in Groups 2 and 4 by oral gavage at a volume of 10 mL/kg for a final dose of 160 mg/kg. An equivalent volume of Veh was administered to Groups 1 and 3.

Prefrontal Cortex Synaptosomes Preparations: The brain was dissected from rats in Groups 1 (n=8), 3 (n=7) and 4 (n=7) and rinsed in PBS. Tissue preparations from Group 2 were not conducted. The PFC was collected as shown in FIG. 15 and homogenized at 4° C. in homogenization buffer (0.32 M sucrose, 20 mM HEPES at pH 7.4, 1 mM EDTA, 5 mM NaF, 1 mM NaVO3 and protease inhibitor cocktail (Roche; Ser. No. 19/543,200)). The homogenate was centrifuged for 10 min at 2,800 rpm at 4° C. after which the supernatant was removed and re-centrifuged at 12,000 rpm for 10 min at 4° C. The resulting pellet was re-suspended in Lysis buffer (50 mM Tris-HCl (pH 7.5), 150 mM NaCl, 1% Triton X-100, 0.1% SDS, 2 mM, EDTA, 1 mM NaVO₃, 5 mM NaF and protease inhibitor cocktail) and sonicated on ice for 20 s at 50% amplitude. The protein concentration was determined by Bradford assay and all samples were mixed with loading buffer (60 mM Tris-HCl pH 6.8, 20 mM DTT, 2% SDS, 10% glycerol, 5% β-mercaptoethanol and 0.01% Bromophenol blue) and stored at -20° C. until WB analysis.

Western Blot Analysis: Western blot analysis for GluR1, PSD95 and GAPDH was performed as previously described (Li, N. et al., Science 329(5994): 959-964 (2010)). Briefly, synaptosomes (15 μg protein) were loaded into 10-15% SDS PAGE gel for electrophoresis and transferred using transfer to a polyvinylidene difluoride (PVDF) membrane in transfer buffer (10× premixed electrophoresis buffer containing 25 mM Tris, 192 mM glycine, pH 8.3; Bio-Rad). The PVDF membranes were blocked for 1 hr at room temperature with blocking buffer (2% BSA in PBS-T (10 mM Phosphate, pH 7.4, 2.7 mM KCl, 137 mM NaCl and 0.1% Tween-20)) and subsequently incubated with primary antibodies: rabbit anti-GluR1 at 1:1000 (Cell Signaling; #13185), rabbit anti-PSD95 at 1:1000 (Cell Signaling; #9644) and rabbit anti-GAPDH at 1:1000 (cell signaling; #5174) in blocking buffer overnight at 4° C. The next day, membranes were washed 3 times in PBS-T buffer, and incubated with horseradish peroxidase conjugated anti-mouse or anti-rabbit secondary antibody at 1:5000 to 1:10000 (Vector Laboratories Inc) for 1 hr. After final three washes with PBS-T buffer, bands were detected using enhanced chemiluminescence. The blots then were incubated in the stripping buffer (2% SDS, 100 mM P-mercaptoethanol, 50 mM Tris pH 6.8) for 30 min at 50-55° C. followed by three washes with PBS-T buffer. The stripped blots were kept in blocking solution for 1 hr and incubated with the primary antibody directed against GAPDH for loading control. Densitometric analysis of total immunoreactivity for each protein was conducted using NIH Image J software. The resulting densitometric readings were used to generate a ratio of total protein to GAPDH. The resulting ratio was further normalized to NS-Veh group for each protein.

Results. The results for bodyweight measurements are summarized in FIG. 16. Rats were randomized into 4 groups by body weight on study day minus 21 so that their mean body weights were the same at the start of the CUS procedure. Groups 1 (n=14) and 2 (n=14) were housed in their regular cages. Groups 3 (n=14) and 4 (n=14) were subjected to CUS from day minus 20 to day 0 (note: one animal from each of these groups died during the CUS thus, the data from day minus 21 is from an n=13 in each group). After 21 days (day 1), non-stress (NS) rats had gained an average of 180.1 g while CUS rats gained 15% less weight (134.9 g) compared to the non-stress group (p<0.0001). The results for the SPT are summarized in FIG. 17. The SPT was performed on day 1 (24 hrs after dosing). In NS rats, the mean ratio of 1% sucrose to water consumption was equivalent in the Veh and NV-5138 groups (0.78 and 0.76, respectively). In contrast, rats in the Group 3 showed decreased preference for sucrose with mean 1% sucrose to water ratio of 0.59 (p<0.05 compared to all other groups). Rats in Group 4 had a preference for sucrose solution that was identical to that of Group 2 (ratio of 0.79). The results for the NSFT are summarized in FIG. 18. In Groups 1 and 2, the latency to feed was significantly decreased 48 hrs after NV-5138 treatment from 596.7±24.7 s to 430.6±25.3 s (p<0.01). After 21 days of CUS, rats in Group 3 exhibited an increased latency to feed (773.9±36.2 s) compared to Group 1 (p<0.01, 596.7±24.7 s). Treatment of CUS animals with NV-5138 significantly decreased the latency to feed to 520.1±40.35 s in Group 4 compared with (773.9±36.2 s) in Group 3 (p<0.0001). No significant differences in home cage feeding was observed immediately following the NSFT suggesting that decreased appetite was not a factor in these results. There was no effect on home cage feeding. The results for the Western blot analysis of GluR1 and PSD95 in crude synaptosomes are summarized in FIG. 19. The concentrations of both GluR1 (panel A) and PSD95 (panel B) in Group 3 were significantly decreased (20%) compared with Group 1 (**p<0.01). Treatment with NV-5138 led to normalization of both synaptic markers 24 hrs post-dose (**p<0.01 for GluR1 and *p<0.05 for PSD95).

TABLE 10 Study Design of Example E Treat- In ment Con- Be- vitro Weight (Days dition- havioral end- Group n sex (g) Route 0 & 5) ing Tests points Group 1 14  M 175-200 Oral Veh NS SPT, GluR1 Group 2 14  M 175-200 Oral NV, NS NSFT & 160 PSD95 mg/kg by WB Group 3 14¹ M 175-200 Oral Veh CUS Group 4 14¹ M 175-200 Oral NV, CUS 160 mg/kg

Table 10: Study Design of Example E Example F: The Dependence on mTORC1 Activation for the Pharmacological Activity of NV-5138 in the Forces Swimming and the Novelty Suppressed Feeding Tests Following a Single Oral Administration in Rats

Study Design. Twenty (20) male rats weighing between 175 and 200 g were randomized into 3 study groups (n=6-7/group), following a 5-day acclimation period. All rats were surgically implanted with bilateral IT cannulas in the PFC 2 weeks prior to dosing. On the day of dosing, all treatment groups received bilateral IT infusions (0.5 μL/side) containing of either the rapamycin (R) vehicle (Veh-R, 10% DMSO) or rapamycin (R, 0.01 nmol/μL) which has been previously shown to completely inhibit mTORC1 activity. Thirty minutes following the intrathecal infusions, either NV-5138 vehicle (Veh-NV, 0.5% methylcellulose/0.1% Tween-80) or NV-5138 (160 mg/kg) was administered by oral gavage. Each treatment group was assessed at the designated time following oral dosing in FST 24 hrs (day 1) LMA 48 hrs (day 2) and the NSFT 72 hrs (day 3 following a 20 hr period of fasting). LMA was measured to rule out overall changes in generally locomotor activity. The study design is presented in Table 11 with timeline of surgical procedures, test article administration and behavioral tests is provided in FIG. 20

Preparation of Test Articles. Rapamycin (Cell Signaling; #9904) was prepared in a solution of 10% DMSO (Veh-R) to a final concentration of 10 μM. R or Veh-R was administered bilaterally (0.005 nmol/0.5 μL per side) into the medial PFC via IT infusion 30 min prior to treatment with NV-5138 or Veh-NV by oral gavage. NV-5138 (lot #07) was prepared by dissolving in Veh (0.5% methylcellulose/0.1% Tween-80) at a concentration of 50 mg/mL. The dosing volume based on the weight of the animal (3.2 mL/kg) was administered by oral gavage to study animals in Groups 2 and 3.

Surgical Procedure and Administration of Rapamycin. Rats were steriotactically implanted with a guide cannula (22GA) into the medial PFC (coordinates from bregma: +3.2 AP, ±1.0 ML, -3.5 DV from dura). Surgical procedures were carried out under the anesthesia of Nembutal (i.p. 55 mg/kg). Postoperative care consisted in peri-surgical administration of carprofen (5 mg/kg) and topical triple antibiotic. After a 2-week recovery period, R (0.01 nmol in 1 μL for PFC infusion) or Veh-R was delivered at the rate of 0.25 μL/min with an injection cannula (26GA) protruding 0.5 mm beyond the guide cannula 30 min before oral administration of NV-5138 or Veh-NV. The dose of rapamycin was chosen based on previous reports demonstrating effective and selective inhibition of mTORC1 activity.

Results. The results for the FST are summarized in FIG. 21. There was a significant 46% decrease in immobility time (the primary measure of efficacy in this model) comparing the Veh-R/Veh-NV group to the Veh-R/NV-5138 from 268±11 s to 144±15 s, respectively (p<0.0001). This difference was eliminated by the prior infusion of R indicated by the lack of significant effect on immobility time between the R/NV-5138 and the Veh-R/Veh-NV groups and the significant difference comparing the Veh-R/NV-5138 compared with R/NV-5138 (p<0.001). The results for the LMA assessment are summarized in FIG. 22. There were no significant differences in the LMA between treatment groups. The results for the novelty-suppressed feeding test are summarized in FIG. 23. There was a significant 46% decrease in latency to feed (the primary measure of efficacy in this model) by 32% comparing the Veh-R/Veh-NV group (747±68 s) to the Veh-R/NV-5138 (510±50 s) (p<0.05). This difference was eliminated by the prior infusion of R indicated by the lack of significant effect on latency to feed between the R/NV-5138 and the Veh-R/Veh-NV (FIG. 23, panel A). No significant differences in home cage feeding as measured by overall food consumption were observed immediately following the NSFT.

TABLE 11 Study Design of Example F Treat- Treat- Be- Weight ment ment havioral Group n sex (g) Route 1 Route 2 Tests Group 1 7 M 175-200 IT Veh-R Oral Veh-NV FST, Group 2 7 M 175-200 IT Veh-R Oral NV-5138 LMA, (160 mg/kg) NSFT Group 3 6 M 175-200 IT R(0.01 Oral NV-5138 nmol) (160 mg/kg)

Example G: Duration of Behavioral Changes in the Forces Swimming Test and Novelty Suppressed Feeding Test After A Single Dose of NV-5138 of Ketamine

Study Design. Forty-eight (48) male rats weighing between 175 and 200 g were randomized into 6 study groups (n=8/group), following a 5-day acclimation period. A single dose of all test articles was administered on day 0 and the behavioral tests were performed 3, 7 and 10 days later. Groups 1 and 2 were dosed on day 0 with NV-5138 (160 mg/kg by oral gavage) and Ket (10 mg/kg by i.p. injection), respectively and subjected to a FST on day 3. The rats in Group 3 and 4 received a single dose of the NV-5138 vehicle (Veh) or NV-5138 (160 mg/kg), respectively, by oral gavage on day 0. The rats in Group 5 and 6 received a single dose of the Ket vehicle (Sal) or Ket (10 mg/kg), respectively, by i.p. injection on day 0. The rats in groups 3-6 were subjected to a FST on day 7 and a NSFT on day 10. All rats in groups 3-6 were fasted the night before for 20 hours the NSFT. The study design is presented in Table 12. The timeline of test article administration and behavioral tests is provided in FIG. 24.

Results. The results for the FST are summarized in FIG. 25. Treatment with Ket significantly decreased the amount of time that male rats spent immobile in the FST performed 3 days after a single dose by 31% (137.9±12.18 s compared to 95.5±7.8 s in the Sal Group 5 vs. Ket Group 2, respectively, p<0.05). Similarly, treatment with NV-5138 significantly decreased the amount of time that male rats spent immobile in the FST performed 3 days after a single dose by 39% (145.3±16.99 s compared to 87.9±9.0 s in the Veh Group 3 vs. NV-5138 Group 1, respectively, p<0.05). Ket significantly decreased the amount of time that male rats spent immobile in the FST performed 7 days after a single dose by 31% (137.9±12.18 s compared to 95.0+11.1 s in the Sal Group 5 vs. Ket Group 6, respectively, p<0.05). Similarly, treatment with NV-5138 significantly decreased the amount of time that male rats spent immobile in the FST performed 7 days after a single dose by 34% (145.3±16.99 s compared to 96.0±11.3 s in the Veh Group 3 vs. NV-5138 Group 4, respectively, p<0.05). The results of the NSFT and the home cage feeding control are summarized in FIG. 26. No significant difference was observed between the Sal and Ket-treated rats or between the Veh and NV-treated rats. There was no difference in home cage food consumption between groups 3-6.

TABLE 12 Study Design Example G Weight Behavioral Group n sex (g) Route Treatment: Tests Group 1 8 M 175-200 Oral NV-5138 (160 mg/kg) FST day 3 Group 2 8 M 175-200 i.p. Ket 10 mg/kg FST day 7 Group 3 8 M 175-200 Oral Veh NSFT day 10 Group 4 8 M 175-200 Oral NV-5138 (160 mg/kg) Group 5 8 M 175-200 i.p. Sal Group 6 8 M 175-200 i.p. Ket 10 mg/kg

Example H: Physiological Changes in the Layer V Pyramidal Neurons after a Single Dose of NV-5138

Study Design: Sixteen (16) male rats weighing between 175 and 200 g were randomized into 2 study groups (n=8), following a 5-day acclimation period. On study day 0, rats received a single dose of either NV vehicle (Veh, 0.5% methylcellulose/0.1% Tween-80) or NV-5138 (160 mg/kg), by oral gavage. On day 1, 24 hrs after dosing, rats were sacrificed, and brain slices were prepared and subjected to whole cell patch clamp recording of layer V pyramidal neurons in PFC. The study design is presented in Table 13. The timeline of the test article administration and physiological analysis is summarized in FIG. 27.

Preparation of Test Articles: NV-5138 (Navitor, Lot #07) was prepared by dissolving in Veh (0.5% methylcellulose/0.1% Tween-80) at a concentration of 50 mg/mL. The dosing volume based on the weight of the animal (3.2 mL/kg) was administered by oral gavage to study animals. Test articles were prepared the day of dosing.

Brain Slice Preparation: Brain slices were prepared according to published procedures (Liu, R. J. et al., J. Neurosci. 22(21): 9453-9464 (2002)). Briefly, rats were anesthetized with chloral hydrate (400 mg/kg, i.p.), in adherence to protocols approved by the Yale Animal Care and Use Committee. After decapitation, the brains were removed rapidly and placed in ice-cold (4° C.) artificial cerebrospinal fluid (ACSF) in which sucrose (252 mM) was substituted for NaCl (sucrose-ACSF) to prevent cell swelling. A block of tissue containing PFC was dissected and coronal slices (400 μm) were cut in sucrose-ACSF with an oscillating-blade tissue sheer (Leica VT1000S). After placement of the slice in a submerged recording chamber, the bath temperature was raised to 32° C. Known concentrations of drugs dissolved in ACSF, applied through a stopcock arrangement at a fast flow rate (4 mL/min), reached the slice within 7-10 s. The standard ACSF (pH=7.35) was equilibrated with 95% O₂/5% CO₂ and contained 128 mM NaCl, 3 mM KCl, 2 mM CaCl₂, 2 mM MgSO₄, 24 mM NaHCO₃, 1.25 mM NaH₂PO₄, and 10 mM, D-glucose. A recovery period of ˜1-2 h was allowed before commencement of recording.

Electrophysiology Recording. Pyramidal neurons in layer V were visualized by video microscopy using an Olympus BX50WI microscope (×60 IR lens) with infrared differential interference contrast (IR/DIC) video microscopy (Olympus), according to published procedures (Lambe, E. K. & Aghajanian, G. K. Neuron 40(1): 139-150 (2003)). Low-resistance patch pipettes (3-5 MΩ) were pulled from patch-clamp glass tubing (Warner Instruments) by using a Flaming-Brown Horizontal Puller (model P-97; Sutter Instruments). The pipettes were filled with the following solution: 115 mM K gluconate, 5 mM KCl, 2 mM MgCb, 2 mM Mg-ATP, 2 mM Na₂ATP, 10 mM Na₂-phosphocreatine, 0.4 mM Na₂GTP, and 10 mM HEPES, pH 7.33. Neurobiotin (0.3%) was added to the pipette solution to mark cells for later imaging. Whole-cell recordings were performed with an Axoclamp-2B amplifier (Axon Instruments). The output signal was low-pass-filtered at 3 KHz, amplified/100 through Cyberamp, digitized at 15 kHz, and acquired by using pClamp 9.2/Digidata 1320 software (Axon Instruments). Series resistance, monitored throughout the experiment, was usually between 4 and 8 MΩ. To minimize series resistance errors, cells were discarded if series resistance rose above 10Ω. Postsynaptic currents were studied in the continuous single-electrode voltage-clamp mode (3000 Hz low-pass filter) clamped near resting potential (75 mV±5 mV) to minimize holding currents. After completion of recording, slices were transferred to 4% paraformaldehyde in 0.1 M phosphate buffer and stored overnight at 4° C. Slices were then processed with streptavidin conjugated to Alexa 594 (1:1000; Invitrogen) for Neurobiotin visualization in labeled cells.

Spine Density Analysis. Labeled neurons within layer V of anterior cingulate (Cg1) and prelimbic mPFC (Cg3) were imaged with a two-photon Ti:sapphire laser scanning system for analysis of spine density and morphology (810 nanometers; Mai Tai, Spectra Physics, Mountain View, Calif.) coupled to direct detection Radiance 2000 BioRad laser scanner (Zeiss Micromaging, Thornwood, N.Y.) mounted on a Olympus BX50WI microscope, using a 60× (0.9 numerical aperture) water-immersion objective. This includes the total number of spines on proximal and distal tufts of layer V neurons, as well as the spine head diameter, and indication of spine maturation. The length of apical tuft branch segments is determined within the 3D matrix of each Z-stack by using Neurolucida 10.2 (MicroBrightField). Spine density and spine head diameter analysis are done with the Autospine module of Neurolucida Explorer (version 10.2) on the raw image stacks (2-5 optical sections, 1 μm apart). Spine density and segmentation (beading) were sampled in three zones: tips of tuft branches as they approach the pial membrane, intermediate dendrites approximately midway between the pial membrane and bifurcation of apical trunk, and proximal tuft dendrites just distal to the bifurcation. Results were expressed in terms of total dendritic length, spine density, and segmentation density. Results were expressed in terms of spine density per 10 μm.

Results. The results of the whole-cell patch recordings of layer V pyramidal cells are summarized in FIG. 28. After a single dose of NV-5138 significantly increased the frequency of 5-HT- and Hcrt-induced EPSCs relative to vehicle-treated rats. Eight rats were used per groups and 3 to 5 cells were recorded per rat. Voltage clam traces of 5-HT and Hcrt-induced EPSCs are shown in FIG. 30. Cumulative probability distributions of 5-HT and Hcrt-induced EPSCs and the effect of NV-5138 are shown in FIG. 31. The results of the dendritic spine density and morphology analysis are summarized in FIG. 29. A single dose of NV-5138 revealed a significant increase in overall spine density with a specific increase of “thin” and “mushroom” spine subtype in layer V pyramidal neuron dendrites. Images were taken from 1 slide per animal, 4 Veh and 5 NV-5138 treated rats from Groups 1 and 2 respectively. There was a significant increase in the total density of apical dendrites of mPFC layer V pyramidal neurons 24 hr following a single oral administration of NV. Significant increases were noted in the specific morphological dendritic spine subtypes designated “thin” and “mushroom.” NV-5138 administration also significantly increased the frequency of both 5-HT- and Hcrt-induced EPSCs relative to vehicle-treated rats which is similar to that previously observed for ketamine (Li, N. et al., Science 329(5994): 959-964 (2010)) but distinct from GLYX-13 using similar procedures (Liu, R. J. et al., Neuropsychopharmacology 42(6): 1231-42 (2017)). This study demonstrates that direct mTORC1 activation following a single oral administration of NV-5138 results in an induction of functional dendritic spine formation, which has been implicated in increased synaptic signaling and improvement in mood for other rapid acting antidepressant agents.

TABLE 13 Study Design Example H Weight Physiological Group n sex (g) Route Treatment Analysis Group 1 8 M 175-200 oral Veh EPSCs Group 2 8 M 175-200 oral NV (160 mg/kg) recording, dendritic spine density

Example I: Behavioral Changes in the Forced Swim and Novelty Suppressed Feeding Tests After Daily Dosing of Compound or Every-Other-Day Dosing of Ketamine

Study Design. Twenty-four (24) male Sprague Dawley rats weighing between 175 and 200 g were randomized into 4 study groups (n=6/group), following a 5-day acclimation period. On study day minus 1 rats were subjected to a pre-swim. Beginning on study day 0, rats in Groups 2 received a dose of Ket (10 mg/kg) on alternate days (day 0, 2, 4, and 6) each by i.p. injection. The rats in Groups 1 received a daily dose of Veh by oral gavage for 7 days (days 0 to 6). The rats in Groups 3 and 4 received a daily dose of NV-5138 (40 or 80 mg/kg) for 7 days (days 0 to 6) each by oral gavage. All rats were subjected to the FST on day 7, 24 hrs after last dosing. On day 8, 48 hrs after last dosing, the LMA of all rats was measured in an open field. Rats were then fasted for 20 hrs and subjected to the NSFT on day 9 (72 hrs post-last dose). The study design is presented in Table 14. The timeline of the test article administration and the behavioral tests is summarized in FIG. 32.

Preparation of Test Articles. Ket (Sigma, cat #K1884) was dissolved in Sal at a concentration of 10 mg/mL. Injection volumes (i.p) of 1 mL/kg of Ket were administered to Group 2. NV-5138 was prepared by dissolving in Veh (0.5% methylcellulose/0.1% Tween-80) at a concentration of 50 mg/mL. The dosing volume based on the weight of the animal (3.2 mL/kg) of Veh or NV-5138 was administered daily by oral gavage to study animals in Groups 1, 3, and 4, respectively. Test articles were prepared the day of dosing.

Results. Results for the day 7 FST are summarized in FIG. 33. Results for the day 8 LMA are summarized in FIG. 34. Results for the day 9 NSFT and the home cage feeding control are summarized in FIG. 35. Significant effects of NV-5138 were observed at 80 mg/kg in the FST and the NSFT. Ketamine produced significant effects in both tests. No significant effects were seen in LMA or home cage feeding.

TABLE 14 Study Design of Example J Weight Behavioral Group n sex (g) Route Treatment Tests Group 1 6 M 175-200 Oral Veh FST, Group 2 6 M 175-200 i.p Ket (10 mg/kg) LMA & Group 3 6 M 175-200 Oral NV-5138 (40 mg/kg) NSFT Group 4 6 M 175-200 Oral NV-5138 (80 mg/kg)

Example J: Marmoset Human Threat Test

Study Design: Thirty-six (36) marmosets (Callithrix jacchus) were paired and divided randomly divided into treatment groups. Twenty-four hours before the Human Threat Test (HTT) animals were treated with vehicle, ketamine (0.3 mg/kg; i.m.) or NV-5138 (160 mg/kg; p.o.). The following day, the same animals were treated with either vehicle (s.c.) or chloriazepoxide (1 mg/kg; s.c.). The animals were then monitored for the number of threat postures over a two (2) minutes period with the presence of a human observer. Locomotor activity was monitored over the same period, as measured by the number of jumps observed.

Results: The number of threat postures for the animals is summarized in FIG. 36. The number of jumps for the animals is summarized in FIG. 37. The data confirm that ketamine induces an anxiolytic/antidepressant-like profile in marmoset HTT twenty-four hours after acute administration without significant changes in locomotor activity. However, half of the animals (6) developed mild emesis (data not shown). NV-5138 produced similar anxiolytic/antidepressant-like effects without locomotor impairment. Importantly, adverse effects, such as emesis, were not observed. Chloriazepoxide yielded similar results. 

1. A method of treating treatment-resistant depression in a patient in need thereof, said method comprising administering to said patient a compound of formula I-90 or a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable composition thereof:

in combination with an antidepressant therapeutic agent. 2-20. (canceled)
 21. The method of claim 1, wherein the antidepressant therapeutic agent is an antidepressant selected from bupropion, venlafaxine, mirtazapine, duloxetine, amitriptyline, and imipramine.
 22. The method of claim 1, wherein the antidepressant therapeutic agent is an antidepressant selected from selegiline, nortriptyline, trazodone, desvenlafaxine, and aripiprazole.
 23. The method of claim 1, wherein the antidepressant therapeutic agent is a selective serotonin reuptake inhibitor (SSRI).
 24. The method of claim 23, wherein the SSRI is selected from sertraline, escitalopram, citalopram, fluvoxamine, fluoxetine, and paroxetine.
 25. The method of claim 23, wherein the SSRI is sertraline.
 26. The method of claim 23, wherein the SSRI is escitalopram.
 27. The method of claim 23, wherein the SSRI is citalopram.
 28. The method of claim 23, wherein the SSRI is fluvoxamine.
 29. The method of claim 23, wherein the SSRI is fluoxetine.
 30. The method of claim 23, wherein the SSRI is paroxetine.
 31. The method of claim 1, wherein the compound of formula I-90 and the antidepressant therapeutic agent are administered in combination to the patient in need thereof simultaneously or sequentially.
 32. The method of claim 1, wherein the compound of formula I-90 and the antidepressant therapeutic agent are administered in combination to the patient in need thereof in separate unit dosage forms or together in a single unit dosage form.
 33. The method of claim 1, wherein the pharmaceutically acceptable composition comprising a compound of formula I-90 further comprises a pharmaceutically acceptable carrier, adjuvant, or vehicle.
 34. The method of claim 1, wherein the pharmaceutically acceptable composition comprising a compound of formula I-90 and an antidepressant therapeutic agent further comprises a pharmaceutically acceptable carrier, adjuvant, or vehicle.
 35. The method according to claim 1, wherein the treatment-resistant depression is resistant to first line treatments.
 36. The method according to claim 1, wherein the treatment-resistant depression is resistant to second line treatments. 